The “Bayview Four” investigate their main suspect at the Homecoming dance.

Five students enter detention, but only four come out alive and they all have secrets to kill for.

The “Bayview Four” go to Simon’s wake and become official suspects in his murder.

The “Bayview Four’s” secrets start to drop; Cooper faces the biggest test of his sports career.

Gus’ expedition with Dr. Singh leads to several shocking discoveries. Big Man and Aimee seek refuge and reinforcements. Becky connects with a new friend.

As Big Man reckons with sins of the past, Gus becomes a target of anger and suspicion, Rani’s misgivings multiply, and Becky begins basic training.

General Abbot makes an example out of Gus. Dr. Singh obsesses over his research ahead of an important presentation. Becky crosses paths with a frenemy.

The zoo turns into a battle zone when the rescue mission takes flight, with families coming together — and falling apart — during the chaos.

An uneasy alliance forms over plans to free Gus and the other kids from captivity. Desperate for a breakthrough, Dr. Singh conducts a risky experiment.

An unsettling discovery at sea forces Gus to take on a grim chore as tensions swell between his companions. On land, an enemy interrogates Becky.

As polar night looms, Gus and his crew arrive at the outpost — but they’re not alone. To find Birdie and the cave, they must brave several obstacles.

After a daring rescue, Gus meets an individual well-versed in hybrid history. Amid emotional reunions and eerie revelations, all roads lead to the cave.

With loved ones beside him, Gus goes on a treacherous journey into the cave to find a cure once and for all. Meanwhile, chaos breaks out at the outpost.

After suffering an unimaginable loss, Gus must make a choice that will determine the fate of humans and hybrids. Who will be left to tell their story?