Alison collects 10 stump-tailed macaques being retired from a research facility in Edinburgh. The journey is potentially dangerous as the stumpies have never been outside before and some of them are old and frail. Back at the park, staff are anxious as chimp Athena undergoes an eye operation, while squirrel monkey Fidget is a hit with the ladies.

Geriatric Gerald is rushed to the operating theatre, having recently lost weight and developed swellings on his body. Alison enlists an unusual helper to test a tracking device as she prepares for an important trip to Vietnam, and baby golden-cheeked gibbon Mikado moves in with foster mum Alex.