Phyllis Summers (Michelle Stafford) is making a deadly vow to stop Diane's (Susan Walters) engagement with Jack (Peter Bergman) in The Young and the Restless. Phyllis is still in rage after losing her daughter and believes that Diane is stealing away her daughter's father. To stop the engagement, Phyllis makes a deal with the devil, Jeremy Stark (James Hyde), who agrees to help her if she joins him in his plan to destroy Dark Horse from within. Jeremy wants to use the masked gala ball to make his move in secret, but Phyllis worries about the risk of being exposed. Jeremy convinces her to move forward and "keep an eye on her." Phyllis is torn between revenge and secrecy.

Meanwhile, Jack has returned to the Abbott house with Diane's dress for the gala. The couple agrees to announce their engagement at the event, despite Phyllis's hostility. Diane is suspicious of Phyllis's behavior and follows her out the door after planting something in her purse, making it clear she knows Phyllis is up to something.

As Phyllis and Jeremy's plan to take down Dark Horse from within slowly unfolds, the stakes get higher, and the likelihood of it backfiring grows. Will Phyllis's desperation to stop the engagement lead to her downfall? Only time will tell on The Young and the Restless.