Kristen, Acosta, and Ben are called to investigate an insidiously addictive Christmas song that's spreading among an increasing number of students.
While it seems to be an earworm at first, the team discovers the Christmas song is playing in the background of a makeup tutorial video from a social media influencer named Malindaz.
Ben then figures out, there's an audio message in the video that only those under the age of 16 can hear. The message is a "suicide instruction meme."
The team confronts Malindaz, and after talking with her therapist, Townsend, she takes the video down and apologizes. It was Townsend who provided Malindaz with the audio recornng in the first place.
Acosta goes to confessional and reveals he and Renee slept together. The priest absolves him, so long as he promises not to do it again.
As Acosta leaves, he is attacked and stabbed by an unknown man.
After Lexis confides to Sheryl about being bullied, Sheryl tells her granddaughter to punch the bully.
Lexis tells her parents that it was Sheryl's idea, but Sheryl lies to Kristen and says she never told Lexis to do that.
Sheryl later calls Townsend, and viewers learn it was his idea to have Sheryl advise Lexis to hurt the bully.