In 1914, a group of British soldiers is preparing to leave England to fight on the Western Front in France, led by Captain Chris Baldry Alan Bates. He appears at one final farewell party thrown by his wife, Kitty Baldry Julie Christie, who finds him withdrawn and distant throughout. Captain Baldry's cousin, Jenny Baldry Ann-Margret, who lives with Kitty, is also anxious because they have heard nothing from Chris's regiment, though Kitty dismisses her fears, more concerned by rising grocery prices and food rationing.
Their quiet war is shattered by the unexpected visit of Margaret Grey Glenda Jackson, who has received a telegram from Chris. She says Chris is ill and has returned to England, but does not reveal more. Kitty refuses to believe her and has her ejected. Only when she reads the telegram carefully does she realise that her husband is in a hospital in London. When they visit, Kitty and Jenny see he is being treated for shell-shock. Chris doesn't remember Kitty, and instead asks for Grey. Humiliated, his wife departs, not entirely convinced he isn't shamming.
After a few days, Captain Baldry returns home, which seems alien to him. He fails to recognise former friends, despite their efforts to reach out to him. He is more amused by simple pursuits, such as walking and staring into the river. He shows little interest in Kitty, and they sleep in separate rooms. He sends for Margaret and they recall their shared past. He had been in love with her despite his parents' opposition to her due to her working-class roots. They had a quarrel, had been forcibly parted, had accidentally lost touch and had married others. Kitty is hurt and furious that he shows more interest in Margaret than in herself.
A medical expert, Doctor Anderson Ian Holm advises that they allow Chris and Margaret to see each other more, something agreed to by a reluctant Kitty and by Margaret's understanding husband, William Grey Frank Finlay. As their relationship blossoms, it becomes apparent that his attachment to her is one of a childlike nature.
Kitty desperately wants him to be cured, and to return to the authoritative pre-war man she had known. Anderson is less keen to cure the Captain, noting how happy he is. To return him to the present, the horrors of the war and the memory of a son he lost to illness would be cruel. He doesn't even remember the child. Finally they resolve to tell Chris about the child, seeing it as a spur that will "cure him." As Kitty watches from a window, Margaret tells him. His body demeanor changes visibly and he starts striding towards the house, looking as his cousin Jenny remarks, > every inch a soldier. Kitty realizes that her husband has come back to her, even though he will likely now be sent back to the war.
