Taking Seth's advice to "embrace the friend," Ryan tells Marissa that he supports her relationship with Oliver. Who should then be introduced as a transfer student to Harbor High School? Oliver himself! Ryan grows increasingly frustrated with the time that his girlfriend spends with this new, unstable presence in her life and he decides to break into Oliver's personal file in order to find out about his troubled past. Ryan gets caught. Dr. Kim meets with Ryan, Sandy and Kirsten and says that the act is grounds for expulsion, but also clarifies the confidential letter that Ryan found in the file: two years earlier, Oliver had attempted suicide over a girl that he had been in love with. The girl has requested a restraining order against him.
Afraid for Marissa's safety, Ryan steals and reads a love letter that Oliver had put in her locker. Through Dr. Kim, Marissa learns of Ryan's mischief, explains that the letter was intended for Natalie and leaves Ryan alone in the hallway, crying that she can't trust him. At the end of the episode, Ryan apologizes to Oliver, but the mentally unhealthy antagonist confirms Ryan's fear; he says that you "can't fight fate" and that Ryan should just back off. Ryan tackles and punches Oliver as Marissa enters the room and the credits roll.
In other news: Seth and Anna continually discover, to their dismay, just how similar they are. Meanwhile, Seth learns that Summer considers him to be the funniest person she has ever met and his interest in her is evident. Julie is hired as an interior designer in Kirsten's company and Jimmy and Sandy officially buy the restaurant, The Lighthouse.
"The Rivals" File: