Contains spoilers for this episode and earlier episodes.
Terry Marsh, an old friend from Lightman's youth, pulls him into a counterfeit-money deal. Lightman's ability to read people is valuable to criminals who need to know whether the notes are convincing. His loyalty keeps him involved even when Terry's account stops making sense. The men behind the deal force him to assess the counterfeiter directly, raising the danger for both friends while Gillian and the staff worry about his disappearance.
An FBI operation interrupts the exchange, and Lightman discovers that a participant was working undercover. He secures Terry's release on condition that he leaves the country and never returns. Afterwards, Terry admits resentment helped him use the friendship, and Cal confronts him about the staged encounters. Cal still considers the old debt paid: Terry once took the blame for a shared offence and spent three years in prison, allowing Cal to escape that future.
Torres and Loker investigate a student's video threat at a school. They discover that Stacey has been bullied, with a teacher's abuse encouraging classmates to treat her as an outcast. Rather than accept his attempt to dismiss her distress as an isolated breakdown, they confront him with the warning video he concealed. Stacey speaks about what he did, and the obstruction investigation threatens his access to pupils. Back at the office, the team challenges Cal for risking himself without asking them for help.