Jonathan is over groomed and has gone bald, while Tom, one of the alpha male capuchins, has died. Elsewhere, the chimps are given walnuts and Jestah gets more than his fair share.
Alison Cronin travels to Monkey World's new endangered primate sanctuary in Vietnam, and meets the newest resident of the centre, Ellie the young golden-cheeked gibbon. Two rare monkeys are being kept in a theme park outside Ho Chi Minh City.
Mueller's gibbons Adidas and Dalumie head for the treetops for the first time, while Peanut, Pung-Yo and Tien move into the enclosure next door. Plus, a specialist doctor is called in when Freddy's bowel complaint fails to improve.
Chimp Ben's foot infection has led to the amputation of one of his toes. Just as he's improving, Honey, one of the chimps in Hananya's house, is struck down by the mysterious bacterial infection - and it is serious.
Chimp Ben's mysterious infection has spread to some of the others in his group, and it's a race against time to diagnose and treat it effectively. Meanwhile, the orang-utans are watching their weight, but are not so keen to get onto the scales.
Chimp Ben has a nasty infection and animal director Jeremy is worried it may lead to him losing his foot. Elsewhere, golden-cheeked gibbon Tien has undergone a transformation, and keeper Holly checks up on Xuzy.
There is a scuffle between the female capuchins, Tia needs surgery, and orang-utan Amy is heavily pregnant - and very grumpy. Meanwhile, there is something new in the play area of the chimp nursery, and Alison has her last visit with Paulo.
A visit from the vet awaits one of the park's strangest residents, while the small monkey team lose the battle to save tragic marmoset Koba, who had been taken out of the pet trade.
Alison travels to Hampshire to rescue marmoset Clyde from a life in the pet trade, while the young orangutan Hujan gets to meet with older male Bulu in the nursery.
Elderly marmoset Jenny gets a visit from the vet before the arrival of a new life partner, while orangutan youngster Hujan begins to adjust to living life in the nursery.
It is moving day for young male orangutan Hujan, who is on his way to join the nursery group, while Alison tries to help rescued marmoset Koba build up some much-needed strength.
Rescued marmoset Koba clings to life after arriving at the park in a stricken state, and the lemurs at Malagasy find themselves dealing with a quite tricky tree-top challenge.
Newly arrived squirrel monkey Kimbo has a heath check and also gets the snip, while orangutan youngster Kayan goes outside for the first time.
A challenging trip into the great outdoors awaits some of the lorises from the park, and two black-shanked douc monkeys have quite the adventure in store for them in Vietnam.
The park comes to the aid of two marmosets, leaving Alison shocked by the condition of the male, while Louisa reaches out the foot of friendship to male crush Matty the capuchin.
Alison attempts to rescue a squirrel monkey, who proves to be something of an escape artist, and the newly arrived orangutan youngster Kayan meets with Bulu Mata for the first time.
Alison visits Twycross Zoo to collect an orphaned orangutan in need of a new home, plus there is some startling news about a capuchin recently rescued from a life in the pet trade.
Woolly monkey Piquita requires an operation, new capuchin Louis gets a lovely perch, while the chimp team find themselves trying to navigate a double blow after two sad losses.
Alison finds herself on a mission to rescue a marmoset that is being kept in a hamster cage, and chimp Kangoo takes his time deciding whether to venture into the outdoor enclosure.
Orangutan Silvestre arrives in Switzerland to be the leader of a small group, and Alison decides the best option is to separate Sasha and Kangoo so they can have a chance at a fulfilled life.