A search-and-rescue mission is mounted to find Juliette, who has fallen into an uncharted cave containing ancient Indian bones.

Peter visits his father while in New York trying to get a loan, and back at the school the students dread taking their PSATs.

To teach the kids to work as a team, they are entered in the Junior Eco-Challenge competition.

Sophie gives the group a parenting assignment, and Katherine's behavior with her boyfriend threatens her impending graduation.

After a student commits suicide, Hannah resigns and the school's founder decides to take the group on a trek to the site of his son's death 22 years earlier.

As the students are recruited to help search for a six-year-old girl lost in the woods, Auggie tries to learn the reasons behind Shelby'a apparent unconcern for the child.

Auggie's older brother tries to talk him into selling drugs to the rich kids at Horizon, while potential investors visit the school, and Sophie and Peter try to figure out their relationship.

As a thunderstorm causes the school to flood, Shelby's attempt to seduce Scott brings him unpleasant memories.

Daisy returns home with Sophie and Shelby for her mother's funeral and must face her abusive, drunken father. Meanwhile, the Cliffhangers read and identify with Mary Shelley's ""Frankenstein"".

Peter gets hooked on pain killers. Scotts mother comes to vist. Shelby comes back to horizion.

Juliette is devastated when she isn't invited to her mother's wedding; Ezra is devastated when he learns that his parents' apparent reconciliation is a sham.

After Auggie and Juliette run away, Auggie is arrested for stealing food, and Peter must try to obtain his release at a probation hearing.

Troubled Scott is brought to the school against his will, as Peter learns that the bank is foreclosing on the school property.

Scott travels down a treacherous river, trying to run away after an encounter with his abusive stepmother. Meanwhile, Shelby falls in love with a horse that's been abused and abandoned.

Horizon's new boss wants to make a promotional film that uses actors instead of the actual students, and Scott's real mother shows up seeking to regain custody of him.

PARENTS WEEK! Scott and Shelby get into a fight. Juliette meets Auggies parents. Shelby's sister runs away from home and to Horizon. Scott lies and tells his father his step mother never abused him (but she really did). When Juliette goes to make herself throw up she ends up talking to Shelby and they sort-of become friends. After Jess gets to Horizon and tells Scott & Shelby her awful story, Scott begins to understand what Shelby went through.

When a tough father brings his troubled son to the school, the kid soon antagonizes the other students as the father treks through bear country with Peter.

When an undercover reporter shows up to do an expose on the school, the students feed her the wild stories that she wants to hear.

Peter's brother arrives to contest their father's will; Sophie undergoes a medical procedure; Shelby's mother pulls her out of school to take care of her ailing, formerly abusive stepfather; Ezra steals the plot of Romeo & Juliet for his new play.

As a winter storm moves in, the kids' solo treks are ruined, Shelby becomes lost, and Peter's visiting father has a heart attack.

Scott tries to get Peter to get Shelby back to Horizon. Shelby finds out her stepfather abused her little sister Jess.

Scott's dad comes to take him back home. Scott tries to convince Shelby they can stay togeather even if he dosen't stay at Horizion. Kat talks Peter & Sopie in to having a MORP. David is back and Ezra is upset because Daisy like David and not him. Scott get into a fight with his dad on their way home an makes him take him take him back to Horizion, and when he gets back Shelby asked him why he came back and he said ""because I love you."" Sopie asks Peter to marry her.