"Subject to Contract" is the 173rd episode of Casualty and the 21st episode of the 10th series.
A man, Phil has been contacted by his estranged wife Pam, who left him for another woman, Helen, while pregnant. Helen is angry with Pam but she feels Phil has the right to know their daughter Daisy has leukaemia. Pam, who is due to donate bone marrow, is hit by a motorcycle while arguing with Helen. Although she is likely to recover, she will be unable to donate so Helen goes to Phil for help, despite worrying she will be pushed out. Jude learns Daniel is taking anti-depressants and asks Baz to help him. A teenage boy goes jogging in his underwear in the middle of the night and sprains his ankle. His father tries to ignore his strange behaviour but, at the hospital, he takes his mother and Kate hostage with a knife and says he hears voices. Kate is annoyed when Trevor bursts into the cubicle and overpowers him; the staff suspect he has schizophrenia. A girl working at an old people's home takes an elderly man in for a check-up only for him to die suddenly. Rachel decides to go with Mike and they slip away quietly while the rest of the staff are celebrating Ash and Laura's engagement.