Charlotte starts her new job as a Governess for the mysterious Alexander Colbourne. Alison seeks to be reunited with her knight in shining armour, and Georgiana receives bad news. Meanwhile, Tom and Colonel Lennox make plans for Sanditon's development.

Charlotte and Alexander Colbourne reach an understanding as she & Col. Lennox enjoy a close encounter at the Midsummer Fair. Alison is falling for her new beau Captain Carter, unaware he's wooing her under false pretenses. Clara calls on Esther for help.

Tension mounts for Charlotte when Colbourne and Colonel Lennox reunite at Lady Denham's annual Garden Party. Georgiana learns a vital piece of information about her inheritance, and Alison's much desired proposal nearly ends in tragedy.

Lennox and Colbourne's rivalry over Charlotte comes to a head and Georgiana makes a decision that will impact her future, forever. Edward's manipulation of Esther takes a dark turn and Alison realizes what she has been missing.

Alison prepares to leave Sanditon with her dreams of romance in tatters, and Esther faces a bleak future. Charlotte considers what her future will look like. When Sidney's belongings are returned to Sanditon, Georgiana learns some shocking truths.

Fiance in tow, Charlotte arrives back in Sanditon for Georgiana's 21st birthday party, but seeing Colbourne again leaves her feeling uncertain. Meanwhile, Georgiana receives a shocking threat, and Edward tries to prove he is a changed man.

Georgiana faces a nearly impossible task, but help arrives from a surprising place, which results in Charlotte and Colbourne being thrown together again. Lady Denham accepts a new vision for the town and enjoys sparring with an old flame.

The day of Georgiana's trial arrives, and she gets a surprise visit from an old friend. Colbourne's shooting party goes ahead, and as he gets closer to Lydia, Charlotte must confront all that she's lost.

Charlotte attempts to distance herself from Colbourne, but as they are repeatedly thrown into each other's orbit, their chemistry rises along with Ralph's suspicions. Meanwhile, Georgiana is unraveling and makes a surprising decision to protect herself.

Charlotte and Colbourne rush to Augusta's aid, and it's revealed whether Edward has really changed. Georgiana is reunited with a ghost from her past, and Charlotte must make a difficult decision about her future.

Charlotte desperately wants to tell Colbourne the truth about her feelings, but a shocking revelation stops her in her tracks. Having opened her heart, Georgiana's worst fears are realized when she discovers she has been abandoned.