Sherlock Sub -

“The barges carried industrial diamonds,” Sub said calmly. “You didn’t want the barges. You wanted the cargo. And you hid them here to divert suspicion.”

Thorne panicked. Sub smiled. “You forget, Irene. I’m a student of pressure.”

His vessel, the St. Mary’s Log , was a retrofitted salvage submarine, all brass periscopes and humming sonar. His “Watson” was a grumpy marine biologist named Dr. Aris Thorne, who’d rather study bioluminescent algae than chase criminals in the murk.

“Brilliant. But now you’re in my tide pool.” Her sub’s claws scraped the St. Mary’s Log ’s hull. “Flood your ballast tanks, or I’ll crack you like a crab.” sherlock sub

“Impossible,” Thorne whispered. “They weigh forty tons each.”

“Sherlock Sub. Always looking down. Never up.”

He’d noticed the glove’s stitching—a rare waterproof sealant used only in deep-sea industrial fans. And the oil slick wasn’ engine oil; it was a synthetic lubricant for hydraulic thrusters . Someone had built an underwater conveyor—a giant, silent pump—to suck the barges into this lair. And you hid them here to divert suspicion

The answer surfaced in the form of a woman’s laugh, echoing through the sub’s hydrophone.

Thorne stared at the churning Thames. “So what now?”

“Look there, Thorne,” Sub murmured, tapping the sonar. A ghost bloomed on the screen: a wreck, not on any chart. I’m a student of pressure

Sherlock Sub lit his pipe—waterproof, naturally—and puffed a ring of smoke that dissolved into the fog.

In the grey, drizzling chill of a London February, a different kind of detective was on the case. Not Holmes of Baker Street, but Sherlock Sub — the city’s only underwater consulting detective.