John could heard Sherlock's steps running behind him on the gravel ground, the sound of their bumping books a monotonous 'thud thud thud' and his own blood pumping deafening loud in his ears. Please, Lord, don't let me be too late, please… When they arrived almost in front of the cafeteria, Sherlock overtook John thanks to his long legs and opened the outer door first. They stopped all of a sudden once inside, aware of the amount of eyes staring at them, hundreds of students eating lunch and chatting calmly, as if everything was alright, as if they didn't have a violent rapist among them, a wolf into the flock of sheep. The other security guard approached them slowly, frowning. John and Sherlock looked around, breathing deep, ready to start running again if necessary, but then they saw her: Nell was sitting at her usual table, with Marcie, Rick and a couple of girls from another group. They were engaged in a lively conversation, it seemed, but Rick, Nell, and Marcie were completely aware of their triumphal entrance. The security guard stopped close to John, clearly waiting for an explanation.

"Sherlock, go with them, I'll go in a minute", John asked.

And he turned, trying to give the guard his best charming smile.

Two minutes and an elaborated lie after, he approached the table were his pupils were sitting down.

"Lydia, Rose, sorry, we have to go now", Marcie said to the other girls. "John promised to give us five minutes of his time before the afternoon periods to check our group task. You don't mind, right?"

And with that, Nell, Rick, Sherlock and she stood up and followed John out to the corridor.

"I think I'll stay… I need a tea anyway", Sherlock said.

John saw Simon sitting with his friend not too far from them across the crowded room, and nodded. As soon as they closed the door, he gathered the boys close around him and told them Sherlock's thought. Nell face fell.

"That can't be possible. No! Why me? I've never talked more than a couple of sentences with him."

"Sherlock can be wrong", Rick hurried to add. "He's not infallible."

But Marcie was thoughtful.

"I don't know, Nell, I'm sorry but I think that Sherlock may be right. I have noticed how Simon looks at you, too. And last year…"

"That was nothing! I was only being nice to him!"

"Yeah, we both know that, but Simon is really shy, and I have never seen him talking much with any girl, so perhaps he thought…"

"Hey, hold on!" John interrupted. "I can't follow you, what happened last year?"

"Are you talking about that time that Nell defended him?" Rick asked. "If it's so, what would he want to hurt Nell? That makes no sense…"

"You defended him?" John tried to keep up. "What happened?"

Nell sighed.

"Some boys from Sixth Form accused Simon to steal money from the gym's locker room. They even went to our tutor, and I don't know why, but the man believed them. Simon was incredibly embarrassed and wasn't able to say anything. I think he was just overwhelmed and panicked, and he couldn't cope with the situation and say anything to defend himself. And everybody stared in silence, it was so wrong! So I stood up and told the boys and the tutor that Simon was obviously innocent, and said to them the places where their money could have fallen and lost. The tutor went with the boys to the locker room and, of course, they found their stupid money and afterwards they had to beg pardon to Simon."

"So Simon is in debt with you", John said, hesitant.

"I don't get it", Rick said, shaking his head.

"Simon was so grateful that started to be very nice to Nell", Marcie followed, grabbing her friend's arm. "And he asked her to go with him to the End of the Term party."

"And you said 'no'", John added.

"But he wasn't angry or anything!" Nell almost shouted. "This is stupid. It can be me. He acted completely normal after that, and the same this year."

John sighed and came closer to the girl, trying to keep his voice calm.

"Simon is an unbalanced person, Nell; someone capable of hurting Claire and Saskia that way… like an animal… is not normal. Please keep that in mind."

The afternoon lessons' bell chimed, and the cafeteria's door opened violently, pushed by a huge group of students joining them at the corridor.

"What do we do now, John?" Rick asked, worried. "Perhaps Nell should stay at home until we find what to do…"

"Or we could set a trap and get rid of this plague for good", said a deep voice at their backs.

They turned in time to see Sherlock smiling, inches from them. Simon and his friend were behind him and coming closer to the door.

"Nell and I will watch him, together", Marcie said at once, and the other girl nodded.

"Talk later?" Rick said, and started walking towards a group of nerdy boys, who greeted him with a smile.

Simon, his friend, and their tails passed in front of John and Sherlock and got lost among the crowd. John suddenly frowned and addressed Sherlock with an accusatory index at his chest.

"You! Come out of here, you git."

He strode towards the teachers toilet, waited until nobody was looking and stepped in. He made Sherlock a 'come in' gesture and waited for him, keeping the door open. The boy followed him, looking uncertain, and went inside. John checked that the two stalls were empty, and closed the door with his key, keeping it in the keyhole.

"Can I know what the hell you were thinking about? Why didn't you tell us you knew the next victim would be Nell?"

John was trying with all his will to keep his voice even and not to shout, but it was being hell to achieve. Sherlock looked a bit lost now.

"I only deduced it yesterday!" the boy said at last.

"And why didn't you tell me yesterday, then?"

"I was going to… but then you invited me to lunch today. I couldn't… I didn't want to ruin it, a date with you…"

Sherlock looked really upset now, his mouth a tight line and his bright eyes lost somewhere in the wall tiles. John breathed deeply. He's a fucking teenager, what did you expect? Calm down and stop scaring him more, for god's sake!

John coughed and talked again, calmer this time.

"Sherlock, that was selfish, alright? Nell is in danger, and we must protect her; that comes first. Do you understand it?"

The boy nodded, still tense, but looking John in the eye.

"Now, you should go to your classroom or you will arrive late."

"Are you angry at me?"

Sherlock's voice broke a little at the last word, and John's heart broke a little too. He stepped forward and hugged Sherlock, tight, inhaling the scent of his hair.

"Of course not. How could I."

They parted a bit, still grabbing each other's arms.

"You said we could set a trap. Send me a whatsapp later if you come with an idea on how to do it."

Sherlock nodded.

"I'll do. I know exactly how we can do it. John…"

I know, Sherlock. The boy leaned in John's personal space and kissed him deeply, his hands running through John's short hair. There was a desperate note in his kiss, and John acknowledged it; he drew soothing patterns on the boy's back, eager to reassure him. But he had to let go soon, too soon, and both sighed and parted ways.

When the first message from Sherlock arrived, John still had the scent of his pupil's hair in his nose, in his head. He read the string of instructions (simple, logical, seemingly easy), and tried to focus on what was more important, and that wasn't the unusual pounding of his mad heart, but the endangered life of Nell. He passed the information to Nell, and she did the same with Marcie and Rick. If everything happened without further complication, the next day all that awful matter would be finished.

Beyond any doubt, Friday was the best day at Greenwood, the main feature being that Sixth Formers didn't have afternoon lessons. In fact, John only had one hour of school availability and then a Department meeting, and afterwards he was free to go home if he wished. He checked his wrist clock: still ten o'clock. He wandered for a while in the cafeteria, letting his tea go cold and unable to focus in his bundle of homework to grade. His mind went back then and again to how Nell would handle her part: during that morning, she had to ensure that Simon overheard her telling to Marcie she was going to stay at the lab at lunch time, since John had lent her the key and allowed her to do some more practice exercises on her own; so no need for Marcie to wait for her after the last period.

God, the plan seemed so weak now! It was perfectly reasonable last night, what the hell had changed? John was sweating, and his stomach churned. What if Simon didn't buy it and found out instead that they were after him? What if he attacked Nell when she was really alone? What if…? Oh, God, just leave it alone. Won't do vomiting right now and having to go back home, will it? John breathed deeply once, twice, thrice. He checked the time again: still not eleven. He groaned in defeat.

At last, he got up and went back to the staffroom. Being in company surely would do wonders for his nerves. There wasn't anybody from the Chemistry Department, sadly (they had all went home after the meeting, it seemed), but he was still able to distract himself for a while chatting with a couple of English teachers, and when they had to go he was again steady and cool head. He turned again to the tasks he had to grade, after that to the internet and then, at last, it was almost one o'clock. He prayed his visit was punctual; there had never been most at stake at punctuality that at that moment. John could feel the cold sweat in the palm of his hands while the other teachers started to appear in the staffroom, greeting each others, exchanging jokes, oblivious to his suffering.

"John!"

He jumped, startled, since he was watching intently the door and didn't notice the hand on his shoulder.

"Jesus!" he gasped, on turning and seeing Molly. "That was a good start you gave me… I didn't know you still were in the school."

"I was at the Department, preparing lessons… Are you feeling alright?"

"Oh, yes, sure. I'm…. ah, waiting for a parent."

"Ouch". Molly did a disgusted face. "Who's the little offender this time?"

"No, none of that, in fact… It's just… oh, I think he is here, excuse me."

John got up in a hurry and reached his hand towards the man standing at the door, who was looking around as if looking for someone. John had no time to waste.

"Mr. Hurt?" he asked.

The man didn't nod, but his gaze focused on John as if in acknowledgement. He didn't look much like his son, his hair fairer and his complexion broader, but there was a certain family likeness that reminded John of Rick.

"I'm John Watson, sir. Really pleased to meet you". If you knew to what extent… "Would you mind to follow me? Rick must be waiting for us, and I bet he is hungry, so I won't take much of your time."

"Of course", the other man agreed.

Molly waved from the door.

"See you on Monday, John! Have a nice weekend."

John looked at her to wave her back and realised, horrified, that she was still wearing the while lab coat.

"Are you still going to work at the lab?"

The girl shrugged.

"Oh, just for half an hour or so. I wanted to test an experiment before taking the lads there on Tuesday."

Mr. Hurt was staring at them with a blank face, so John tried to solve this quickly.

"Actually, I was going to talk with Mr. Hurt in the lab, Molly. Rick is surely already waiting for us there. Would you mind running your test next Monday? I can help you at lunch time, if you want; it will be quicker."

Molly nipped her lower lip, but she smiled at once and started to take her lab coat off.

"Sure, no problem."

Thank goodness, John thought, sighing loudly, relieved. That was close. He took his coat and his bag and led the way out; Mr. Hurt followed him along the packed corridor and upstairs until the second landing. There he stopped, looking annoyed because of the many thumps he was receiving from the distracted students who were going down the stairs on their way home, unaware of the loose jolting of their backpacks and their effect on the passing people.

"Are you sure we wouldn't be more comfortable in the hall? The other times I have come to an interview with a teacher we always went to a small office near the Head teacher's one…" the man said.

"Well, yes, but I thought that, being Friday, and with everybody so agitated, you know, we would be quieter in the lab, actually…" John waffled.

Mr. Hurt sighed in clear annoyance, but kept going upstairs. John stopped him at the next fourth landing, the one that led to the second's floor corridor, before the man crossed the landing door. John could now see Sherlock across the corridor, pretending to be talking on his mobile phone, pacing distractedly while the remaining students cleared the corridor. At the sight of John, Sherlock lowered his phone and slipped inside an empty classroom (the arts one, John recalled). Good. Now I only have to wait for his signal. He couldn't believe everything was working according to their plan, it was too good to be true.

"Oh, sorry, do you mind?" John exclaimed suddenly, taking out his own phone and feigning to be answering a phone call. "Hello? Yes, it's me… Excuse me, who is that?... Ah, yes, I was expecting your call." John checked again Sherlock's position. The boy turned to look at him from his hiding place and shook his head, so John extended his fake conversation. "Oh, I don't think I can make it next Tuesday, I'm a bit behind on the schedule already… Could we meet next week instead?... Oh, too bad. When, then?"

Mr. Hurt was starting to fidget impatiently, and put his hand on the door, clearly intending to wait for him in the corridor. John jumped to interpose his body between the man and the door, his mind streaming to find an excuse, any excuse, and finding none.

"Mr. Watson", Mr. Hurt said between gritted teeth. "I think I'll wait in the lab with my son, if you don't mind."

"Wait! The door is locked; hold on a moment while I finish this call and I'll go and open the lab". Mr. Hurt didn't seem very convinced. John begged again, cursing inwardly. "Please. This phone call is really important for me."

The man hesitated a moment, and then nodded. John sighed into the phone and carried on his pretended phone call. Suddenly, the device buzzed. He looked at it, startled, and saw a new whatsapp sent by Rick.

'Can I join you now? Is my dad with you?'

He hurried to answer, checking Sherlock at the other side of the door, still in his hiding place, and forgot completely that he was supposed to be having a phone conversation.

'Yes, please. 2nd floor landing, right stairs'

"Excuse me, can you tell me what is going on here?" Mr. Hurt asked, angry. "You didn't even tell me why you wanted to talk about Rick, and as long as I know, he is getting good grades and never got into trouble. So if what you have to tell me is not important, perhaps we could set another meeting when you are more focused…"

"Dad!"

Saved by the bell, John sighed. Rick was climbing the stairs two at a time, smiling nervously at his father. Mr. Hurt seemed to relax at the sight of his son, and he moved to go downstairs again.

"No, dad, wait!" Rick exclaimed. "Has Mr. Watson shown you our experiment yet?"

"What? No, nothing of the sort."

"Oh, but you must! It's the main reason he wanted you to come to the school, you know?"

Mr. Hurt smiled, obviously pleased.

"Ah, so this was what your teacher was so mysterious about! And I was thinking you had gotten into trouble!"

"Who, me?" Rick laughed.

John patted Rick's back, joining in laughing. Then he turned to check again Sherlock's position and his heart jumped: the boy was gesturing him as a madman! Time was up!

He looked at Mr. Hurt, his eyes wide with alarm but suddenly mute. He hadn't pictured how he was going to do that! Fortunately, Rick was aware of the situation and grabbed his father's arm without hesitation, pulling him quickly through the landing's door.

"Come on, dad! No time to spare now!"

John ran along the corridor, trying to be as silent as possible, while Sherlock finally left his hideout and joined him in front of the lab door. They looked at each other and nodded, Rick and his father directly behind them, and then they pushed open the lab door with a loud 'thoud!'

John knew what was going to see, and he thought he was ready to take that in, but he was wrong. When he saw that huge lump of a body thrown over the smaller frame of Nell… the girl's body leaning over a lab desk, and that beast forcing her down with his big, strong, rough hands… He felt like vomiting, right then, right there. But Sherlock had already jumped the other young man's back, and Simon, who was already startled by the intrusion, struggled a bit to throw Sherlock off to the ground. John was ready to join the fun when he saw a shine in the corner of his eye.

"Sherlock! He's got a knife!" he shouted.

Too late, oh God, too late!, he thought, because Sherlock suddenly caught his stomach with a grimace of pain, but he didn't let Simon go. John was already punching Simon on the jaw; the massive boy rolled over and fell down with Sherlock, releasing Nell, and kicked John from the ground, hard, making him stumble backwards. Sherlock elbowed the other boy's neck and sat up, trying to push himself on top of Simon.

Suddenly some strong hands took charge of the situation, producing a pair of handcuffs that fitted perfectly around Simon's wrists. The young man looked at them with incredulity painted on his face. John felt like laughing, but first helped Sherlock up and examined his injury: only superficial, fortunately. Although it would require some stitching.

Rick helped Nell to sit down. The girl seemed frightened but alright. Marcie appeared at the door, at last, and she quickly ran towards her friend, hugging her tightly, while Rick patted her back awkwardly.

"Well, I think I need some explanations… even when I can imagine more or less what's happening here", Mr. Hurt said, smiling at his son. "So this was your… experiment. Good on you, I'm very proud, Rick! And of you, too, of course, kids, but you let this go too far, Mr. Watson. The girl could have been hurt."

"I'm OK", Nell said with a thin voice.

"And the tall boy", he said looking at Sherlock. "I still don't know if you are brave or simply rash. You may be Sherlock, aren't you?"

"You know-it-all arsehole!" Simon howled. "You are going to pay for this! You are dead, you hear me? Dead!"

John's hand on Sherlock's waist tightened, protective. He pushed Sherlock further from the criminal and let go of him, aware of the cop's presence.

"OK, you lot", the man said. "I give you one hour to go home and eat something, and then I want you at the Met local headquarters to make your statements. I'm going to read his rights to this piece of crap here, and then phone for a car and an ambulance."

"I'm OK!" Nell repeated.

"Sure, but we want to take a pic of the current state of your neck, and I want them to take a look also at Sherlock's stab. So please, be quiet and patient for a while, will you? Meanwhile, I'm sure Rick can go in search of the Head Teacher…"

Rick smiled and ran off, clearly happy for being useful. Mr. Hurt took his phone out and made a call. The four of them (the two girls, Sherlock and John) gathered together once more, Nell still trembling as a leaf, Marcie checking now Sherlock's injury.

In the end, John's nerve got sick of waiting and took pics of Sherlock's and Nell wounds on his phone, proceeding then to clean and disinfect Sherlock's one. He didn't have stitching material there, but when he finished with the part he could do the ambulance was already there. He could feel the boy's warm gaze on him the whole time, and had to try hard to not return it, feeling his cheeks already hot and surely blushed. The Head Teacher was only a few feet from them, discussing about security and insurances with Mr. Hurt. John was glad nobody was paying them any attention, and even gladder of going out of the building, at last, although it was to jump an ambulance and stand by Sherlock's side while they stitched him. He was tough, that boy: he didn't whimper or grumble once.

"You again… Why does that not surprise me?" a voice rumbled behind them.

"Sergeant Gregson", John greeted. "I'm glad you have come".

And had seen first hand the brilliance of my brand new boyfriend, he thought. The man nodded, then frowned, and afterwards he opened his mouth to say something, but changed his mind and seemed lost. At last he sighed and just said:

"Let me tell you again, and I hope it's the last time I have to warn you: teenagers must focus on studying, partying and dating nice chicks. Next time, when you feel the thrill of crime-solving is invading your mind… go to the cinema and watch a detective film! Have I made myself clear?"

"Crystalline", John whispered.

The cop turned his menacing frown towards Sherlock, who frowned in turn. John elbowed him, and Sherlock sighed audibly and nodded. Sergeant Gregson seemed satisfied with that answer and let them go. Sherlock pouted.

"Can you believe it? We solve a case for him, and that's his 'thank you'!"

John smiled fondly. Sherlock looked adorable when disgruntled. He leaned towards him and whispered in his ear:

"Do you want to have lunch together and afterwards go to make our statements to the Yard?"

Sherlock's eyes shone with delight.

"Best idea I've heard in ages, Doc!"

The two of them walked away in search of John's car, trying not to touch each other and keep a good foot between them while walking. The Head Teacher, who was now talking with Sergeant Gregson, didn't miss a beat of their way together across the parking lot, though.