The film takes place primarily within the grounds of a sanatorium where a group of young adults are receiving treatment for tuberculosis. Among them is a cheerful young nurse named Catherine (Juliet Mills) who catches the attention of nearly all of the male patients, including flirtatious sailor Norman (Andrew Ray), sarcastic writer Bruce (Donald Sinden), and smooth-talking Canadian Neil (Ronald Lewis).
As the patients undergo their various treatments and routines, they form close bonds and engage in friendly rivalries, all while vying for Catherine's attention. Meanwhile, the stern but caring doctor in charge, Dr. Boyd (Donald Houston), struggles to treat the patients effectively and keep their spirits up.
A major source of conflict arises when one of the patients, the wealthy and entitled Molly (Jill Ireland), refuses to obey the rules of the sanatorium and insists on having her own way. However, the patients ultimately come together to support each other and overcome personal struggles during their stay.
The film's lighthearted tone is punctuated by moments of sadness and poignancy, particularly as the patients each confront the reality of their illness and the potential for a shortened life. However, the overall message is one of hope and camaraderie, emphasizing the importance of friendship and positivity in the face of adversity.
Despite its similarities to the Carry On films, Twice Round the Daffodils stands on its own as a charming and memorable comedy-drama, featuring strong performances from its ensemble cast and a thoughtful exploration of life in a sanatorium.