Helena, John and Henry risk everything to rescue Meiyin from Nerva.

Nerva unleashes a punishing surprise-attack against John's village.

Helena and her friends devise a daring plan to liberate prisoners.

Helena makes allies in a treetop village, and travels to a Pteranodon den.

Helena's on the run from Nerva's scouts, when she meets a new ally: Meiyin.

Paleontologist Helena Walker awakens on an island full of strange beasts.