A key witness in a drug investigation is found dead after escaping from his court-mandated rehab program, and Backstrom must figure out how he escaped and who killed him. However, when the S.C.U. learns that the victim is member of a band and all his bandmates dislike him, they start to believe that the killer may be someone closer than they expected. Meanwhile, Backstrom has reason to believe that Valentine may be more than just his tenant.