The Zhacan roared at them from the other side of the shield charm. John returned his full attention to maintaining its strength, edging himself into a sitting position.
"Alright, then," the Doctor said, walking back to the edge of the shield. "So you've been stealing for your children. Forgiveable. Commendable, even. But that doesn't explain the attacks on the students."
The animal shook its head. The sounds were a bit more pleading, less ferocious, but carrying an unmistakably defensive growl.
"Now don't change the subject –" The Doctor said warningly.
The Zhacan growled again. The Doctor spun on his heel and headed back to the cave.
"This one?" He asked, pointing at the larger of the two cubs.
The creature nodded.
He reached out to it slowly, offering his hand as if to a dog. "There now, I'm not going to hurt you. I just want to have a look. Mummy says it's okay."
Both cubs seemed to vanish. The Doctor sighed. "There's no need for that. We're here to help."
He warily put his hand out further. Lindsay and Sherlock had their wands out on either side, poised for the first sign aggression. John alternated his attention between the scene unfolding behind him and the alien pacing on the other side of his shield charm.
"Come on, you can trust me," the Doctor said, apparently having made contact with the alien's fur. He petted it experimentally. "I'm the Doctor, I'm going to fix it."
The aliens slowly faded back into a blue. The smaller cub was looking at the Doctor with an expression of utter terror, the larger seemed to be relaxing into the caress.
"Alright, then. Mummy says you've got yourself hurt." The Doctor eased the creature into a reclining position and nudged its curled limbs away from its abdomen. John stopped swiveling his head to stare at the long, bloody slice across the cub's stomach and down its left side.
The Doctor hissed in a breath in sympathy. "That's got to hurt a bit. What happened? Try to take down a centaur on your own?"
The cub mewed, but even John could discern the hint of pride in the sound.
"Oh, the thestrals. Aren't you the adventurous one?" The Doctor said. He glanced around at the students around him. "A bit stupid, but adventurous, I grant you. Must be in the air around here."
"You're one to talk," Lindsay muttered.
John laughed. Sherlock let out a sound that could have been a snort or a laugh, it was difficult to tell. The Doctor smoothed the fur back from the injury, shushing the little pained sounds coming from the cub. The mother stopped her pacing and was standing, paws drawn together in concern, watching the Doctor's movements. John braced his elbow against his knee, resting his wand arm for a moment.
There was a screeching snarl from the cub. John's head whipped around in time to see it clawing away from the Doctor's reaching hand. He pulled back, but the smaller cub had gathered itself, hackles raised, and struck with its tail.
The mother Zhacan threw herself against the shield yet again. With John's attention divided, it crashed through the charm, roaring. John scrambled to his feet and backed up, but it was Lindsay's shouted "Protego!" that brought another shield up.
"Thanks," John muttered.
Lindsay nodded, keeping her eyes on the Zhacan. John hurried over to the Doctor, who had fallen over on his side. Sherlock had pulled his sleeve up and was examining the puncture wound.
"How do you feel?" John asked.
"A bit… woozy," the Doctor said, his voice thick.
John leaned over his arm, edging Sherlock aside with his shoulder. "Pain?" The puncture was about the size of a wand tip, but had torn the skin around the wound, creating a slight claw mark across his wrist.
"Not that I can tell," the Doctor said.
"Well, the others didn't experience any pain at first, either."
"Don't be thick, John, it's not the same wound," Sherlock said sharply.
"It's possible the younger ones' venom reacts differently," John said, continuing his examination of the wound.
Sherlock's voice sped up. "The others' marks were completely smooth. Completely. This one has jagged edges. There's no way it could have been made by the same implement. And the students didn't feel a thing when the wound happened. The Doctor, on the other hand, is clearly experiencing the effects of a muscle paralytic. Exactly like what he told us a Zhacan's stinger is supposed to deliver. Lex parsimoniae - we've got two villains in this story. Well, now, that makes it all a bit more interesting, doesn't it?"
"Yeah, a bit," John said, quickly checking the Doctor for any signs that this was anything other than what it appeared.
The Doctor was already pushing himself into a sitting position – his movements slow and jerky, but functional. He pointed to the cub. "Check him out. See if you can do anything about that wound."
John turned warily to the creature, who was staring at him with equal distrust. He held out his hand for it to sniff, which it did with a hint of curiosity. He reached for the wound. It recoiled, showing an impressive set of teeth. Its younger sibling growled.
John withdrew his hand, looking to the Doctor for guidance. The Doctor nodded at him with an effort.
"Just talk to it. It will understand."
"Right," John muttered under his breath as he extended his hand again. "I'll just talk to the cute little alien and hope it doesn't try to bite my fingers off."
"It can hear you, John," said Sherlock, who had trained his wand on the creatures. "Perhaps a bit more diplomacy."
"That's rich," John said, smiling. He made eye contact with the cub. "You don't know how funny that is, but believe me, it's a laugh. Now, I'm going to take a look and see if I can fix this for you. I'll do my best not to hurt you. I promise."
The cub relaxed its limbs and let him see the wound. The spell was a familiar one, but he'd never before performed it on a creature he half-expected to attack his wand. John waved it slowly, repeating the incantation over inch-long segments of the cut. From behind him, he could hear the mother paced and huffing, growling deep in her chest.
"Any chance of speeding that up?" Lindsay called, a laugh in her voice that John wasn't sure was genuine.
"Steady on, John," the Doctor said, smiling encouragingly. It was a bit lopsided, but the thought was clear. "But – as quickly as you can, eh?"
"Anybody else want to volunteer to do it faster?" John demanded.
The other three exchanged glances, but said nothing. John turned his attention to the final segment. The relief that came when it closed up and the skin turned blue like the rest of the creature seemed disproportionate to the act, but he didn't question it.
"There now," he said, releasing the breath he'd been holding for longer than he realized. "You're all sorted. You'll be up chasing creatures you shouldn't in no time."
The cub moved experimentally, then curled into a ball, then leapt up against John, knocking him back on his haunches like a large dog. A shock of something – either surprise or fear – ran through his limbs, but he held himself steady as the claws landed on his shoulders. They did not sink through the fabric, and the expression in the alien's eyes was questioning as it leaned closer to his face.
John could feel Sherlock and the Doctor moving closer. He made the slightest shooing motion with his hand, keeping eye contact with the cub, who was leaning closer until its snout was angled against his chin and its eyes were about two inches from his. The smaller one was edging closer, too, reaching out with one paw.
"Lindsay," the Doctor said, moving with greater fluidity as he rose to his feet and turned toward her. "Go ahead and let the shield charm down."
"What?" The question came from both Lindsay and Sherlock, who looked as if the slightest sound might send him into a frenzy.
"She wants to be with her cubs," the Doctor said. "And she'll be able to control them."
From the corner of his eye, John saw the Doctor walking up to the mother. "Your cubs are alright now. I'm going to let you come to them. But you have to promise me you will leave this place immediately."
The Zhacan gave a ragged sound that John hoped was agreement, because Lindsay let the shield charm down. The mother alien didn't waste any time in reaching her cubs. John kept his position, still keeping eye contact with the inquisitive cub, but expecting –
A heavy paw crashed into his left shoulder, knocking him to the side. There was no claw, but the weight of the blow sent him all the way to the ground, flat on his back. Sherlock scrambled to his side. "Did it hurt you?" he asked, running his eyes over John.
"No, I'm fine," John said, pushing himself into a sitting position.
The Zhacan had cradled both of its young into its lower set of arms. Its upper arms were out defensively, and the expression on its face did not bode well.
"I can take you back to Zhactarm today," the Doctor said. "Are there more of you?"
The Zhacan shook its head, mewing.
"You don't want to go back? Whyever not?"
Another growling roar from the Zhacan, longer, as if it was telling a story.
Lindsay took the opportunity to join the boys. "So this thing didn't poison the students?"
Sherlock shook his head. "It was something else. Someone else. Someone in the castle. It has to be. But who?"
The Doctor laughed. "You had a fight with your mum-in-law and stormed off with the kids and he didn't follow you? Honestly? Worse than humans, you are."
The Zhacan gave a disgruntled snort.
"Well, I'm sorry this is such an inconvenience for you, but you're not staying on this planet. And I think you ought to go home and make things right. Family is important, you know."
The Zhacan appeared to consider this. John brushed the dirt from his robes and looked over at Sherlock.
"It would have to be a very gifted witch or wizard," Sherlock muttered. "You said you, Madam Pomfrey and Professor Slughorn together couldn't identify the poison. That suggests an adult, or someone with very advanced powers."
"Someone like you?" John teased, then caught himself, an idea forming behind the joke. "Someone like Jim Moriarty?"
Sherlock's eyes narrowed. "Possibly. Though it's a bit ostentatious for his style."
The Zhacan snorted suddenly, shaking its head.
"Come on, now," the Doctor said chidingly. "Don't be like that. I'm sure he misses you."
Another snort.
"Alright, so he should have come after you. But he didn't, and you could go on being mad at him and planet hopping forever, or you could take your kids and go home – let them grow up in a proper nest with lots of friends and no strange creatures coming after them night and day. Or you can choose some other planet at random and hope for the best. I just think my way seems easier."
Sherlock was frowning in concentration. "Someone who could create something like that –"
"And has access to students from all four houses a different points during the day," John said. "The poison was delayed, remember? We had people coming into the hospital wing over more than 12 hours. Not someone too impatient, I suppose."
"And Victor said the poison had traces of the samples from the Zhacan. So someone who knew about the –" Sherlock broke off, eyes sliding out of focus, mouth going slack.
"What? What is it?" John asked.
Sherlock turned on his heel and started running back toward the castle. "I know who the poisoner is!"