David Anthony, a Harley Street physician, swaps duties with his brother, a medical missionary in Africa.

Following a group of five very different student nurses during their first year of training at an NHS hospital in London called St. Augustine’s Hospital (filmed at Guy's Hospital), where they live in a dormitory. Susan (Belinda Lee) is reliable and sensible; Pat (Delphi Lawrence) is flighty and open; Maureen (Adrienne Corri) is Irish and loud; Ann (Henryetta Edwards) is a typical public school girl; and Liz (Barbara Archer) comes from a typical working class background. As they get to know each other, they bond in spite of their differences.

Esther and her sister Jennifer have just taken a remote country cottage. But there is strange gossip about the previous occupants.

When a pharmacist accidentally prescribes poison instead of painkillers, the race is on to find the killer pills.