In a desperate attempt to keep "his" son from Jason, he kidnaps him and hides him from both Jason and Olivia. Meanwhile, Ruben closes in on the kill drug but isn't sure if he should use it -- and, if so, who of Jason or Ian he should use it on.
An operation on Jordan's son is made even riskier by Jason's ingesting of the unfinished kill drug, which makes Ian's appearances more random than usual.
When a surgery's complications force it to continue after 8:25pm, Jason chances taking Ruben's still-unfinished kill drug to hold Ian off long enough to finish the surgery. The surgery is a success, but the drug doesn't last as long as planned and both Lena and Olivia suffer as a result.
Ruben arranges for a gang to "mug" Ian so that he can get a sample of his spinal fluid -- a necessary element for his pending kill drug, but the plan backfires when Jason is blackmailed by the gang into potentially killing a patient who is a member of an opposing gang.
Jason receives a text message threatening to reveal his secret - but who sent it? Jason's search for the sender reveals there's a thin line between ally and enemy. Olivia, on the run from Ian, takes Cole to a place overrun with memories of an earlier life with his father. Closer to home, Jordan's investigation into Jason's past turns up a promising lead.
Ian breaks an important rule by beating up a man in a bar brawl, which puts Jason's medical skills to the test. Meanwhile, Jason tries to mend his relationship with Lena; and Olivia is unnerved by Ian's stalking.
Jason's attempt to control Ian's spending backfires when the doctor comes to in a random sports car tailed by a drug dealer. Meanwhile, a falling out between Jason and Lena prompts a late-night visit from Ian; Dr. Jordan tries to get to the bottom of Jason's behavior; and Olivia worries about her son's new imaginary friend.