The office of Sherlock's neurologists has been robbed, including his medical records, so he's investigating. Body parts are found at a university lab. The parts came from zoologist William Velnick, known as "The Worm Hunter." Velnick was paying the security head with chemicals to doctor the surveillance footage, so he could hook up with lovers at his lab.  Velnick was naming the worms he found after his sex partners. Donnie Mainzer, the husband of one of Velnick's lovers, admits to shooting him three times. Sherlock said that while Mainzer shot Velnick, someone else killed him. Velnick was wearing a bulletproof hoodie when Mainzer shot him. Sherlock found the man who stole his identity, an Irish illegal immigrant. One of Velnick's sponsors was an armored clothing manufacturer, for whom he was collecting insect fibers. Mason finds who was sending Velnick death threats. She was sending Velnick a virus to steal his data. Velnick stole the hoodie, and the killer stole it back from him. Sherlock figures out which company produced the material used in the hoodie. It's silk from a spider.  One of Velnick's lovers, Sepi Chamanara, stole that kind of spider and had determined how to crossbreed it with silkworms to mass produce enough silk for those hoodies. But Sherlock's theory is that Velnick had poisoned the mulberry trees whose leaves those silkworms eat, and that's why Chamanara killed him. Velnick did that for John Hoyt of Hoyt Armor. Hoyt tells them Sepi saved her trees somehow. Sherlock tracked down the thief who stole his medical records, and the thief said Michael paid him to steal Sherlock's records. Marcus found Velnick's hard drive at Sepi's home. She found out Velnick's roundworms were killing her trees, and she slashed him with a screwdriver.