"Oh, for god's sake, Sherlock. This is the Met Police."

The consulting detective slammed his hands down on Lestrade's desk. "All the more reason to suspect that there is a traitor among you, Inspector!"

Lestrade made a face and folded his arms across his chest. Sherlock bristled at his denial.

Tucked away in the corner, Donovan rolled her eyes. She didn't trust Sherlock Holmes; she never would. And to have a man so arrogant — so acerbic — start tossing around accusations against her colleagues? It was a bloody joke. "So you think one of us is some kind of mole?" She asked with a derisive smile.

"I don't think; I know," Sherlock answered bitterly.

"Right, course you do." She straightened up. "So why 'm I here, then? You've no idea who this supposed traitor is. Maybe it's me." Lestrade snorted. "Seems like a big mistake to bring it up while I'm here if you suspect everyone."

Sherlock glanced at John, who promptly looked to the floor. Lestrade, recognising a potentially dangerous situation, sat up quickly. "Sherlock," he warned — but the consulting detective cut him off.

"Sergeant Donovan," he began snidely. "While it is customary to suspect the individuals closest to the target—" Greg frowned "—as the most outstanding threat, you're not worthy of the incrimination. I have had the misfortune of getting to know you, and ignoring the fact that you all are the least suspicious people alive — however atrocious — the man we're looking for is going to be affable, bland, and unassumingly clever."

"Unassuming? Rules you out," Donovan shot back.

"Quite, and thankfully, clever rules out most of the people working here."

"But not all of them, apparently."

Sherlock smirked. "You would love that recognition, wouldn't you? Please, Sally. A blind nun could see how innocent you are. All bark and no bite, as they say."

Donovan clenched her fists.

"Sherlock, you're wrong."

Sherlock stopped short and stared at Lestrade. "I am not wrong, there is someone in this office—"

Greg cut him off. "Well, yeah — you're wrong about that, too. But you're wrong about Donovan."

The younger man's eyes narrowed. John's brow furrowed in confusion.

"The only reason she hasn't punched you yet is because I routinely beg her not to, but believe me — she will, and I know firsthand the damage her right hook can do. So do yourself a favour and shut up."

Either he was speechless, or he uncharacteristically took Lestrade's advice; regardless, Sherlock remained silent.

"And you are wrong about there being a mole. You can't just waltz into Scotland Yard." Sherlock sneered. "There's background checks and personnel files going back to primaries. We know everything there is to know about the people who work here."

"Not everything," Sherlock snapped.

"Sherlock—"

"I'm never wrong, Lestrade"

Greg pursed his lips. "You know that's not true."

Sherlock's nostrils flared.

He pursed his lips as he fought to prove his hypothesis to two idiots who seemed willing to refute that the bloody sky was blue. But his struggle was interrupted by a brief knock at the door, followed by Dimmock poking his head into the office.

"We're going for donuts, anyone…" His voice faltered as the tension hit him like a breaker on the shoreline. "Yikes."

Lestrade laughed quietly, but it didn't alter the animosity. "Yeah, two of those custard ones, if you can?"

Dimmock smiled, and looked to Sally — who still seemed quite ready to rip Sherlock's heart out with her bare hands. "Coffee. Large. Very large. Mounds of sugar." He nodded nervously.

"Uhh… Sherlock, John. Do you guys want anything?"

John politely declined, and Sherlock rolled his eyes disdainfully. Turning back to the desk, he glared down at Lestrade, who offered him nothing but dismissive sympathy.

"I'm going to meet one of my experts—"

"Your homeless network."

"Who might have information about corrupt policemen," Sherlock finished through clenched teeth.

"Well, let us know how that goes."

Dimmock stepped back quickly as the seething consulting detective whipped past, flipping up his coat collar as he walked. John apologised and hastened after him. Only after they'd left did Dimmock slowly stick his head back into Greg's office. "Somebody woke up on the wrong side of the bed, eh?"

"Is there a right side of the bed with Sherlock Holmes?"

"The one that's on fire," Sally muttered.

Dimmock and Lestrade exchanged worried glances. "I'll be right back with that coffee then, shall I?"

He shut the door and beckoned to the blond officer waiting by the water cooler. His detective sergeant, a quiet and affable Dane, fell into step beside him and noticed almost immediately that there was an unusual urgency in the way his boss grabbed their coats and scrambled to the door.

He didn't even need to ask; there wasn't much that Dimmock kept from him, and of the two of them, Dimmock was significantly more chatty. "Just a slight situation," the young detective inspector confided, in response to the Dane's questioning glances. "Donuts, coffee, and a quick clean-up."

The Dane arched an eyebrow as they hurried out of the building.

A dozen yards away, Sherlock Holmes and John Watson climbed into a cab. Dimmock watched uncomfortably as the little car sped off down the street.

"Problem?" The Dane asked.

Dimmock spun, all trace of awkwardness gone as he frantically searched the road. An old man on the curb fumbled with the keys to a flashy coupé. Dimmock's lip curled in annoyance.

But slightly farther down, a petite woman in a dark business suit rested a to-go cup on the roof of an inconspicuous estate car. Dimmock quickly and quietly explained the plan to his sergeant as they approached.

He flashed his badge, and the woman in the driver's seat protested — but unluckily for her, not loudly enough to draw the attention of the people milling about on the street. The Dane slid into the seat behind her, his necktie wrapped like a length of garotte wire around his hands.

She kicked Dimmock in the arm with the sharp end of her stiletto as the Dane hauled her into the back, but he leapt behind the wheel all the same, knocking her flailing legs away. Her tea lay abandoned in the gutter, but the napkins she'd used to insulate the cup kept Iain's hands from leaving game-ending fingerprints as he eased the car out onto the road.

"I hate bodies," the Dane grumbled a few minutes later. The nameless woman — now an asphyxiated, nameless cadaver — had collapsed into the space between the seats on the passenger's side.

"Don't we all," Dimmock mumbled, scanning the road for a very specific cab.

"That one," the Dane said, his arm resting on Dimmock's shoulder as he pointed to a cab in their lane.

"But where's he going?" the DI asked, keeping a reasonably safe distance.

The Dane frowned. "You said take the woman. I took the woman. I remembered the car number. Now you are asking for more?"

Iain smirked. "Apologies… but either we figure out where they're going, or we'll have more than two bodies to deal with." In the rearview mirror, Dimmock noticed the way the Dane's head tilted to the side. "Her, and Holmes's informant."

"Ah. The bridge."

"What?"

"The woman begging for pennies under the overpass." Dimmock made the turn before his detective sergeant could finish the sentence.

In the back of the cab, Sherlock's eyes narrowed as he peered out the window.

"Something wrong?" John asked, fully aware that Sherlock hadn't heard a word of the lecture he'd been giving about not antagonising the Yarders unless they really had it coming.

"Thought we were being followed," Sherlock answered, shifting in his seat.

"Yeah, well. You would. You're paranoid."

The consulting detective seemed positively affronted. "I am observant."

"Yeah, and people who see all sorts of things that aren't there have a problem known as…"

"Inattentive friends."

John grunted and turned away from him, focusing his attention on the city slipping past the cab's windows. Sherlock smiled.

As they got to the overpass, they found his so-called expert waiting for them — sprawled out on the ground with a bullet hole between her glassy, grey eyes.