|Spoiler Warning: Plot details, ending details, or both are in the text which follows.|
Happy Holidays is the twenty-first episode of the anime.
Michael Müller, now an art dealer, is seen at his house in Nice, France with his wife, Barbara, and her son, Fritz. Michael tells his wife that he sometimes feels as is someone was watching him from the house next door; Barbara tells him that that house is empty.
A private detective hired by Michael updates him on Tenma, Nina and Detective Messener. He tells Michael that Messener was stabbed to death. A memory of the late Fortners haunts Michael. Michael tells his bodyguard, Roberto, how he and Messener were blackmailed into killing the Fortners by some mysterious person and how afterwards they received a large amount of money for the murders.
Michael finds the detective has been killed. Nina enters the house and tells Michael it was Roberto who killed the detective. Nina grabs the detective's bag and forces Michael to drive her away from the house. Michael assumes that Nina has come looking for revenge.
The car pulls and Nina is about to kill Michael next to the sea, but Michael tells Nina about how he met Barbara. Nina spares Michael life and both check the detective's report that states that a person named Roberto was the one who killed Detective Messener. Michael receives a call from Roberto, asking for the detective's bag, threatening to damage Barbara and Fritz.
Nina and Michael return to the house and Michael hands the bag to Roberto, but he learns that Nina was taken away by Roberto's men. Michael goes looking for Nina in an abandoned house. When Nina is about to get killed, Michael saves her by shooting all of Roberto's men. Nevertheless, Michael gets shot.
Nina drives a wounded Michael back to his house.
- A few of Roberto's men
- Michael Müller: "Roberto, who are... who are you?"
- First appearance of one of the main antagonists of the series: Roberto.
- In the anime, Michael's fate is unknown. Nevertheless, according to Another Monster's chapter 6, he dies.