"Love Labours... Lost" is the 450th episode of Casualty and the fourth episode of the 19th series.
New doctor Selena Manning makes a return to Holby A&E after working at the hospital for a brief spell 18 months ago. The police doctors first day gets off to a good start, she happens to bump into Harry who she nearly slept with when she was last on the wards of Holby. However after laughing and joking about their last meeting together Selena arrives home for a big shock - her husband in bed with hospital receptionist Bex. As Fin goes to a press conference to discuss his heroic actions following the fire he ends up being branded a killer by grieving widower Karl.