Within the central group of Ngogo chimps, alpha male Jackson faces possible threats to his leadership and mother-of-two Christine educates her new baby.

In search of fruit, rival chimps from Western Ngogo venture into disputed territory and seize an opportunity to send others nearby a warning.

While some chimps form new bonds, others plot rebellion. Years of bad blood threaten to erupt into violence when a Western raiding party ventures out.

Jackson's injuries leave him vulnerable to enemies and supposed allies alike as a rainstorm sweeps through Ngogo. Will his rule as an alpha end here?