Lucas investigates Dan's (recurring guest star PAUL JOHANNSSON) heart condition while Haley struggles with letting Dan into Jamie's (recurring guest star JACKSON BRUNDAGE) life. Nathan urges Quentin (recurring guest star ROBBIE JONES) to reinvent his game & Brooke juggles her career & life as a new mother. Meanwhile, Peyton tries to assuage her guilt over Lucas' breakup, & Mouth gets a shot at being a sports anchor.