Sherlock burst onto the street in time to see his wife keeling over into his enemy's lap. He had to avert his eyes from her as he reached them, focussing on handcuffing Moriarty and deleting any incriminating pictures of Kaitlin from his phone. That done, there was nothing left to distract him.
Her would-be betrayal cut him right to the heart, like an icy dagger that made it difficult to breathe when he looked at her. But angry as he was, he couldn't quite quash his feelings of needing to protect her. Unable to help himself, he gently sat her up more, so she was leaned back against the bench besides Moriarty, rather than across him, then quickly turned away, distracting himself with telling curious passer-by's that there was nothing to see here, until Lestrade arrived.
"Blimey, John said you got him, but I didn't expect it to be that easy. You even cuffed him for me." Lestrade grinned like it was Christmas.
"Yes I'll still need yours though. For Molly." Sherlock told him, as detached and emotionless as he could be.
Lestrade's face fell faster than a lead balloon. "What do you mean, 'for Molly?' She's never done anything remotely criminal in her life, other than helping you fake your death I suppose." he looked over with fresh concern at the pathologist passed out besides their criminal.
"Oh she's full of surprises" Sherlock replied, a hint of bitterness now colouring his tone. "John and I heard her with our own ears trying to help Moriarty escape our plans. Aiding and Abetting I believe they call that."
Lestrade's eyes widened in shock, glancing again towards the unconscious pair in the bench, then around and the other officers nearby, as if to check that no-one else heard it, before pulling Sherlock aside.
"Sherlock, are you sure?" Lestrade asked quietly "That's a pretty serious accusation, and she's your wife for goodness sake."
"I didn't think the police were allowed to believe in nepotism. Bring her in Detective, and I'll question her myself."
Half an hour later, Sherlock was pacing agitatedly in Lestrade's office, waiting with John and Mary for the tranquillisers to wear off. Mary had taken Kaitlin to her registered address as soon as she got word that Moriarty had been captured, telling her she would be picked up soon. She felt bad for her, expecting her uncle to turn up, when it would in fact be the police taking her into protective custody, ready to turn her world upside down. And then to come back and hear that Sherlock had had Molly arrested… she was not much in the mood for listening to his ranting.
"I can't believe she was going to tell him. I mean, it's one thing agreeing with him over me, but to actually betray our plan to him? I had no idea he had her so wrapped around his little finger. I suppose I should have seen this coming, what with their history. After all, she only broke up with him because of my deduction that he was gay, not the criminal bit, that came out later. I guess she may not have broken up with him if she'd-"
Unable to tolerate it any longer, Mary jumped up from her seat as he was about to pass her for the umpteenth time, and landed a solid smack to his cheek.
"Ow! What the hell was the for?!" Sherlock snapped, his hand cupping his cheek and looking, if possible, even more hurt and betrayed than he already had.
"So you'll snap out of your stupid jealous ranting and start thinking logically again!"
"Jealous? I'm not jealous." Sherlock insisted "What is it with you two?"
"Come on mate, are you even listening to yourself?" John put in from his seat.
"You keep going on about her choosing 'him over you', when her behaviour clearly has nothing to do with him or you, and everything to do with her father." Mary explained.
"Wait, what?" John's head whipped round to look in confusion at Mary.
"What has he got to do with anything? He's dead." Sherlock scoffed.
"Oh!" John said, understanding.
"And how old do you think Molly was when he died?" Mary pushed.
Sherlock was stubbornly silent for a few seconds, not looking at Mary before admitting "Kaitlin's age. Or a little older."
"Exactly. And her Daddy Issues are pretty clear for all to see, you just have to look at the way she looks up to any older man that steps into her labs, there's no way Moriarty would have missed it. He didn't go to Molly because he thought she'd choose him over you, he went to her because he knew it would be only too easy to get her to sympathise with Kaitlin. She didn't have any uncles to stand in as a father figure, and probably envied Kaitlin for it, so felt Kaitlin's pain as her own at the idea of her losing him. She probably didn't give much thought to what Moriarty is besides being Kaitlin's Uncle. It was all about the girl." Mary explained.
Sherlock opened his mouth to reply, then closed it again. Before he had a chance to reassemble his thoughts, Lestrade appeared in the doorway.
"Moriarty is awake. He's ranting something about 'his girl, Kaitlin', we're looking into it. But if he's awake-"
"Then Molly will be shortly." Sherlock finished for him, straightening his coat. "Best not keep her waiting." He stepped around Mary without looking at her accusing eyes and headed for the door, but Lestrade put a hand on his chest to stop him passing.
"Sherlock, I know I already asked this, but are you sure? It's not too late to drop the charges you know."
AN: Not a very long one, I know, I couldn't decide whether this and the next bit should be one or two chapters, but I didn't want to keep you all waiting too long, so opted for two shorter ones. See you in the next chapter :)