Meredith is sent into a state of panic when Derek finds her mother’s diary in the house. Meanwhile, Callie stresses while preparing for her first date with Erica. Later, Cristina…

Murtaugh and Riggs search for the culprit of a local jewelry heist. Meanwhile, Murtaugh gets called “grandpa” by another parent while at the playground with Harper, sending him into a…

Alan and Lyndsey decide to spice things up in the bedroom.

When a villain calling himself the Trickster runs rampant in Central City, Joe and Barry go to Iron Heights to talk with the original Trickster.