A Marine falls ill during combat training. Right after Deeks makes eggs and bacon for Rosa's breakfast, Roberta blows in bearing a box of vegan donuts. Kensi is gone for a week to Quantico for a refresher course. Rosa has come down with the flu. Callen is hunting for Hetty with a satellite. Roberta returns to watch Rosa. The Marine, PFC Edward Hanson, was attacked by a genetic weapon. Kilbride tears into Deeks for being late. Deeks and Rountree talk with Hanson's mother. She says that he had recently taken an interest in cryptocurrency. Hanson's roommate, PFC James Williams, is missing, as are Hanson's phone and car. Sam fears that Hanson and Williams may have been smuggling bioweapons. Fatima discovers Hanson was sending money to unethical researcher Xander Yost. Rountree captures Williams. Deeks finds Yost dead in a freezer. Hanson and Williams had been paying Yost for a muscle enhancer. Williams panicked at the thought of blood tests and ran. Williams mentions that Yost had an assistant. Kilbride sends Fatima to infiltrate Open Source Bio, which bought the monitors worn by Hanson and Williams. Fatima poses as a budding entrepreneur. Fatima is revealed as a Fed by Herman the cyborg but she talks her way out of the confrontation. Deeks tracks down Yost's assistant, Nick Embry. Herman tells Fatima that Embry left Open Source Bio on bad terms. Sam and Callen find Embry's van and determine that he's a proponent of eugenics. Fatima decides that Embry is contaminating the lab's insulin meant for diabetics such as himself. Sam and Callen cut off the lab's delivery van, driven by Embry. He takes Lisa Cho hostage. Lisa uses her implanted hand magnet to grab Embry's knife. Kilbride talks with Deeks about balancing work and home life. Deeks comes down with Rosa's flu.