Charlotte and Sidney clash again, only for Charlotte to be left confused by a chance encounter. Tensions surrounding Miss Lambe's arrival in Sanditon erupt at Lady Denham's grand pineapple luncheon and Esther and Edward realise that Clara poses a significant threat to their ambitions.

The arrival of Miss Lambe's forbidden love causes Charlotte to question her opinion of Sidney. Meanwhile, Clara witnesses a moment between Esther and Sir Edward that raises her suspicions about their relationship, with devastating consequences for Esther.