Contains spoilers for this episode and earlier episodes.
A wealthy woman's request to check her new boyfriend leads Lightman towards George, a man who adapts himself to whatever his partners want. Accounts from several former wives describe different personalities, while a notebook points to a scheme involving lawyer Dobson and powerful local figures. Lily's son Noah has also become attached to George. The apparent romance therefore threatens both the woman's finances and a boy who has started trusting a new adult.
George is reported dead in a garage fire, and Lily's distressed behaviour raises suspicion. Noah confesses to protect her, but Lightman exposes gaps in his story. Lily says George attacked her when she confronted him, and she fled alive. The team follows Dobson's apparent movements and discovers that George survived the fire while Dobson died. George has assumed his associate's place, carrying his habit of becoming somebody else into the murder inquiry.
Confronted with witnesses and the possibility of a capital charge, George agrees to testify against the judge, police chief and others involved in the wider scheme. Lightman reassures Noah that George's photograph of him suggests real affection, though Gillian questions whether Cal simply invented a comforting explanation. At home, Emily returns from visiting Zoe and describes her mother's new partner. Cal listens to her teasing comparison of the men and settles into an ordinary evening with the daughter whose judgment he so often tries to direct.