Ella plans Chloe's bachelorette party. Lucifer and Dan investigate the murder of a dog trainer, with Lucifer taking the lead to "understand" Chloe better. Pierce's mark reappears, which Maze interprets as a sign that Chloe is unsure of her love. Amenadiel recruits Charlotte to break off the engagement. Dan enters a gambling den in search of a suspect, before Lucifer stages a surprise police raid. Maze intentionally throws a boring party and Linda, Ella, and Charlotte hire a party bus instead. Amenadiel tries to persuade Pierce against losing his immortality. The murder suspect reveals that he is an amateur trainer and that his purebred mastiff is expecting puppies that could fetch high prices. Ella figures out that Maze and Charlotte are both trying to manipulate Chloe and stops the party. A drunken Chloe rides off in the bus, while Dan and Lucifer deduce that the victim's partner is the killer and arrest him. Maze learns that Pierce's mark is fake and tries to kill him, but he uses Trixie to force her to leave. Dan expresses his feelings for Charlotte and they begin a real relationship. Chloe ends her engagement and resumes working with Lucifer, angering Pierce.