Staff prepare for the arrival of two new woolly monkeys from Switzerland, but they are worried how the animals will cope with the long journey - and how they will fit in once they get here. The male capuchins are put to the test with a clever puzzle feeder and the female stump-tailed macaques vie for superiority.

Alison travels to Vietnam on a ground-breaking project to release rescued golden-cheeked gibbons Merry and Lee into their natural habitat. But before the pair can be set free, they have to be radio-collared, and this proves difficult when Merry refuses to co-operate.