Johnny dies from head injuries sustained from a drunken fall off of a cliff. Marissa being expelled from Harbor School for shooting Trey. After some help from her friends, Taylor and Sandy, she is readmitted by the school board.

How do Ryan and Marissa get back into Harbor?

He wishes to punish Marissa Cooper who shot Trey Atwood in the back to save Ryan's life, but is only able to expel her. ... At the end of summer dance, Summer sees Taylor and Jack sharing an intimate tryst and Sandy uses the information to blackmail Jack into leaving Harbor to save his career and get Ryan back into Harbor.

Is Marissa in Season 4 of The OC?

Rachel Bilson as Summer, Adam Brody as Seth, Melinda Clarke as Julie, Peter Gallagher as Sandy, Benjamin McKenzie as Ryan, and Kelly Rowan as Kirsten all returned to the main cast. Former main cast member Mischa Barton did not return because her character, Marissa, died in the third season finale.