S4·E1 Post Mortem Madness

Kimberly sets off her bombs, destroying half of the building. MacKenzie suffers a fatal heart attack. Billy breaks down Alison's door and pulls her to safety, although she is blinded by the blast. Peter saves Kimberly from drowning after the impact knocks her into the pool. Kimberly is placed in the psychiatric ward, and is unable to recall the events of the past week. Billy storms out when Hayley calls him to task for not immediately taking Brooke on their honeymoon. Brooke later moves out of the mansion and into Billy's apartment. Jess is killed in the fall from the construction site, while Jake suffers only minor injuries. He shuns a guilt-ridden Jo. The jailed Matt is enraged when his parents seem to suspect that he is guilty of murder. They win back his trust when they put up their mortgage to bail him out of jail.