Justimon's Ultimatum is the twenty-first episode of Gallantmon Strikes.
The Charles Brothers return to Murmuxmon's lair. Murmuxmon confronts them about attacking Gallantmon & reminds them that he doesn't want Gallantmon touched. Murmuxmon then orders them to remove Takato Matsuki from his lair to be "reunited with his loving son".
Lauren enters Gale's Books. Tom informs her that Morgan isn't there. Lauren explains that she's so over being mad at her, & tells him that she's just stopping by because her internet is down & wanted to check her e-mail. Tom lets her use Morgan's laptop in the back room to check her e-mail. Lauren inserts the Flash Drive, & it begins copying Morgan's files. Mako enters, Tom informs him that Kurt & Morgan are on their way to Rosedale Industrial Park & explains that they got a call from Johnny saying that Kurt's father is there. So Mako heads on out to go after them. The Flash Drive completes copying the files, so Lauren takes the Flash Drive & leaves.
Kurt & Morgan find Takato in front of a mirror, next to more mirrors. Johnny then shows himself & reveals to Kurt & Morgan that he is Justimon. Johnny explains that when the Feds imprisoned him, Murmuxmon came & took him out through a mirror, & he has been free ever since. Johnny offers Kurt his dad for Beelzemon's Digi-Deck, but Kurt refuses the offer. The Charles Brothers then show themselves. Kurt tells Morgan to get ready to take his father & get out of there. The four transform, & Gallantmon takes on Sleipmon, TigerVespamon & Justimon by himself. Gallantmon manages to get his dad away from them, & Morgan gets away with his dad. Justimon tells Gallantmon that they don't want to fight him, they want him to join them.
Mako is attacked by two Monsters & transforms. Beelzemon uses Final Vent & destroys the Monsters. Gallantmon is destroying the mirrors. Gallantmon uses Strike Vent & fires, blasting Sleipmon, TigerVespamon & Justimon. Sleipmon takes a direct hit, while TigerVespamon & Justimon are blasted through a mirror & land in the Digital World. Gallantmon then pulls out his Final Vent Card. TigerVespamon & Justimon can only watch as Gallantmon Final Vents Sleipmon. The mirror falls as Sleipmon disintegrates. Sleipmon is Vented. TigerVespamon & Justimon are unable to return through the mirror. TigerVespamon wants revenge for his brother. Beelzemon finally arrives. Kurt gives Sleipmon's Digi-Deck to Mako.
Lauren returns to Mira & gives her the Flash Drive. Lauren asks if there is anything else she can do to help. Mira tells her to just watch Morgan & keep her away from the guys. Lauren takes off. Mira inserts the Flash Drive into her laptop.
Morgan has returned Takato to the hospital. Kurt arrives & informs Morgan that he Vented Sleipmon.
A female Holder intercepts some Minions & transforms into Sakuyamon.