My brother-in-law stole the most dangerous fish in my collection. I didn't call it borrowing. I called it evidence. The koi was blue-and-white, one black spot behind its gill, insured for forty-two thousand dollars—and poisonous enough to kill a grown man. My wife thought it was beautiful. Her brother Miles thought it was worth money. He had a key to our house, a habit of taking things, and a sister who had spent her whole life excusing him. At 10:42 p.m., security footage shows him leaving with the fish in a plastic bag. I saved three copies. Then I told Elena I was reporting her brother for grand theft. She called it a fish. I called it the moment our marriage split open. Now Miles is selling a poisoned trophy to a collector who doesn't know what he bought. And I'm a forensic accountant who never misses a pattern—or forgives one.