"Only the Lonely" is the 138th episode of Casualty and the 10th episode of the 9th series.
A teacher takes his Down's Syndrome son to the swimming pool where he meets with his mistress. While he is breaking up with her, his son hits his head on the water slide. He admits the truth to his wife and their son recovers. A frequent patient known as Professor stabs himself in the toilet and it is some time before Jude finds him in reception; he recovers. Mike attends a rugby match on his day off; the player-manager, Frank, is a friend. Frank's son Rob is moving to London with his girlfriend but stays for the match. Rob punches an opposing player who taunted him and breaks up a scrum, causing Frank to injure his spine. Josh, back on the ambulances, arrives with his new partner Liz, who tries to shoo Mike away, unaware of who he is. Mike tells Frank he may never walk again and Rob decides to stay and look after him.