A doctor's already-shaky marriage is tested to an even greater extent when he has to contend with a smallpox epidemic.
| Actor | Role |
|---|---|
 Claire BloomJulie Monks | Julie Monks |
 Richard JohnsonDr. Steven Monks | Dr. Steven Monks |
 Yolande DonlanRuth Preston | Ruth Preston |
 Cyril CusackFather Maguire | Father Maguire |
 Kay WalshMatron | Matron |
 Michael GoodliffeClifford Preston | Clifford Preston |
 Mervyn JohnsBuckridge | Buckridge |
| UUrsula HowellsJoanna Duten | Joanna Duten |
 Vanda GodsellAgnes Davis | Agnes Davis |
 Norman BirdHarold Davis | Harold Davis |
 Felix BownessWellford | Wellford |
| JJill CurzonNurse Jill | Nurse Jill |
| LLeonie ForbesNurse Vicky | Nurse Vicky |
 Suzan FarmerCarole | Carole |
 John MerivaleMr. Bradley | Mr. Bradley |
 Bruce MontagueBrooks | Brooks |
 David WestonBrian Davis | Brian Davis |
| JJoby BlanshardHealth Inspector Matthews | Health Inspector Matthews |
| Vanda GodsellMrs. Agnes Davis | Mrs. Agnes Davis |
 Ray BarrettHealth Inspector Bennett | Health Inspector Bennett |
 Basil DignamHealth Officer Boswell | Health Officer Boswell |