The WI members of Great Paxford live under a shadow as the Battle of Britain looms on the horizon. Pat befriends a Czech soldier, but finds her newfound independence less enjoyable than expected. Laura faces the consequences of her affair, while Sarah receives some shocking news. Alison strikes a bargain with the police, and tragedy strikes for Frances.

Laura is publicly disgraced when news of the Bowers' divorce hits the papers, with grave consequences for the surgery and her friendship with Tom. Pat is tempted by her feelings for Marek while Bob is in hospital. Steph is delighted when Stan returns home on leave, but the reunion is overshadowed by his fears of invasion. Frances discovers a secret at the reading of the will.

The Czech officers organise a dance to keep morale up as the Battle of Britain intensifies. Joyce has some advice for Sarah which is not well-received, while Pat realises that somebody knows about her relationship with Marek. Allison's secret work for the police leaves her forced to decide where her loyalties lie. Steph fears that Stan is becoming a bad influence on his son, and Frances finds out that Peter's affair was more complicated than she thought.

Pat and Marek are reconciled, but when someone sees them together, their relationship is in more danger than ever. The Brindsleys come to realise the full extent of David's injuries, and Teresa faces letting go of the past when she is asked out. Alison fears the consequences of her involvement with the Lyons, Laura is spurred into action by some happy news, and Joyce and Erica work together on a first aid meeting.

The villagers prepare for harvest time, but Steph struggles to cope with the workload and faces losing the farm if she cannot meet her quota. A newcomer to the community stirs up tension between Sarah and Frances, while Joyce and the Brindsleys also receive unexpected visitors. Teresa faces a big decision, while Sarah finds herself in a dangerous situation. Alison discovers the real reason behind the parachute accidents and makes a horrifying connection to the factory. She races to warn Frances before it is too late.

The village prepares for Nick and Teresa's wedding as the Battle of Britain draws to an end. Pat faces a big decision as Marek prepares to leave, but Bob intends to ruin her plans. Frances fights to clear her name following the closure of the factory, Alison wrestles with her conscience, and a chance encounter leaves Joyce with some unanswered questions.