Gremlin is a nine-week-old baby toque macaque. She was born into a troop of 70 monkeys who live amongst spectacular ruined temples in northern Sri Lanka. Despite the beautiful location, life is going to be a challenge for this little monkey. There are harsh internal politics to negotiate and predators roaming the forest floor. But the biggest threat to her survival comes from a rival troop of monkeys known as the Slumdogs. They are led by a big male called Bad-Eye and the vicious rivalry over territory between the two families threatens to explode at any moment. One in three macaques do not reach their first birthday, and if spirited little Gremlin is going to be one of the lucky ones she will need to learn the lessons of survival fast.