When is a Mon Justimon?

When is a Mon Justimon? is the forty-sixth episode of Digimon Tamers. It was preceded by The D-Reaper's Disguise and followed by His Kingdom for a Horse.

Plot
Justimon has arrived, and is revealed to be Ryo and Cyberdramon biomerged. Before they can go to save Takato and Guilmon from the D-Reaper, a big green D-Reaper agent, Horn Striker, appears, connected to the D-Reaper by his tail. He attacks MegaGargomon and Sakuyamon, but Justimon kicks him away and tells them to rescue Gallantmon while he fights Horn Striker. Kazu and Guardromon decide to help Justimon fight Horn Striker.

Shibumi searches for a way to defeat the D-Reaper, and Janyu wonders how it can be in two places at once, until he finds the D-Reaper's consciousness, realizing that it is a single entity with a single consciousness, and its agents are plugged into and controlled by it, a kernel of artificial intelligence. If they can sever the connection, the tamers might have a chance.

Inside the D-Reaper, Evil Jeri and her version of Jeri's sock puppet imitate everything Jeri said to Takato, while outside, Impmon and Calumon search for Jeri, Impmon wanting to help her to atone for killing Leomon. D-Reaper agents attack them, but Impmon digivolves to Beelzemon, Blast Mode, and fights them. Calumon eventually finds Jeri inside an invisible barrier. Beelzemon punches a hole in the wall, making it visible. It is the kernel sphere of the D-Reaper's consciousness, referred to as the D-Reaper's brain. Calumon enters, but Beelzemon becomes trapped by the D-Reaper's tentacles. Calumon enters the center of the D-Reaper's brain, where Jeri is currently imprisoned, and he is now trapped inside it as well.

Sakuyamon creates a powerful energy shield around herself and MegaGargomon as they enter the D-Reaper, where Evil Jeri is still tormenting Takato with Jeri's lines, momentarily tricking him into thinking she is the real Jeri, until she reveals her true form. As MegaGargomon and Sakuyamon enter, Sakuyamon is suddenly weakened, and turns transparent. As Evil Jeri chases after Takato and Guilmon, MarineAngemon suddenly appears with Kenta and fights off Evil Jeri with Kahuna Waves. Takato can't believe Kenta saved him and Guilmon. When MegaGargomon and Sakuyamon arrive, MarineAngemon heals Sakuyamon with Kahuna Waves, and MegaGargomon clears a hole in the wall of chaos so they can get out.

Justimon and Guardromon fight Horn Striker, and Justimon injures him with Thunder Clap. They appear evenly matched, when Sakuyamon sends a Spirit Strike through Horn Striker's head. MegaGargomon damages him with Guardian Barrage, and Justimon tries to kill him by cutting off his tail, but Horn Striker whips him with it. As Horn Striker tries to bite him, Antylamon pulls on his tail, and Justimon cuts off his tail, severing his connection to the D-Reaper and destroying him.

Henry, Terriermon, Kazu, Guardromon, Kenta, MarineAngemon, Ryo, and Suzie celebrate their victory at Rika's house, Kazu particularly about a time Guardromon saved Justimon from a block of concrete Horn Striker threw at him. Elsewhere at the house, Guilmon looks for Takato, while Rika laments that they never got a chance to thank Alice for what she did.

Alice hears Dobermon's spirit, walks away, and vanishes, implying that she is a ghost.

Takato stands at a higher area, watching the D-Reaper in the distance, and wants to help Jeri. Jeri and Calumon are still inside the D-Reaper's brain, which is set between the towers of the Hypnos building.