New arrival, Scott, settles in to life at Mt. Horizon, while his new group, the Cliffhangers, make their way back from an eventful 10-day quest in the woods.

Peter's old flame, Sophie, and ex-wife, Chloe, both show up for a visit. Juliette makes a play for Scott. Shelby fights her demons as the Cliffhangers help search for a lost girl.

Peter goes to New York to secure financial help from his father to save the school; the students are apprehensive about taking the PSATs.

The teens at Horizon must learn about teamwork when they enter a torturous dawn-to-dusk triathlon. With Joe Lando.

Juliette falls into an uncharted cave and discovers the skeletal remains of an American Indian girl; Peter organizes a search party.

When Katherine is caught in a compromising position with Hank, she jeopardizes her impending graduation from Horizon.