By convincing Chief Wiggum to drive her off in the back of a police car, she creates the illusion that she is a rebel, preserving her new "cool" status while successfully shutting down the party.
She "narks" on her own party by calling the police, but then uses a staged arrest as a social feature.
In the subplot, Lisa organizes a massive slumber party at the Retirement Castle to fix her reputation as a "party pooper".
Homer and Calvin have a bitter prank war because Abe treats Calvin with the kindness he never showed Homer.
Watch this breakdown for a closer look at the rivalry between Homer and his new step brother, Calvin: