The girls go back in time to stop GDD CEO Janet Smythe from starting the corporation, when they learn she is behind the future lab. But their plan prevents other major events from happening in their lives, including them living together, and Barry and Marci falling for each other.

Things spin out of control when Cyd travels back to Christmas the year before to try and figure out the perfect gift for Shelby. Meanwhile, Barry and Naldo's Winter Wonderland experiment sparks an elf war with Bret and Chet leading the charge.