Depthmon is the twelveth episode of Gallantmon Strikes.
Flashback: Sergeant Rayturn says to his son, Charlie Rayturn, that four generations of Rayturn men have served this country, & no son of his is going to break that tradition. Charlie says that "he won't, sir". But the school principal comes with some not so good news. The principal explains to Chalie that his grades took a turn to the worse & he won't be able to perform his duties. Sergeant Rayturn tells the principal to run the tests again, & that there's nothing wrong with his son, & the tests are wrong. The principal explains to Sergeant Rayturn that Charlie will be getting a full month at summer school. Chalie asks the principal to not do this to him, he wants to serve his country. The principal says that there are still many ways to do that, but the Sergeant explains that the Rayturns are Marines, they have always been Marines! The Sergeant has a talk with the principal alone. Murmuxmon then appears & introduces himself to Private Rayturn (Charlie) as Special Agent Simons & explains that he heard about the discharge, & that he works for a Clandestine Governmental Organization, & he is just exactly the kind of young man they're looking for. Agent Simons tells him that what he's about to reveal can never be repeated, not even to his father. Chalie agrees, then Agent Simons gives him a Digi-Deck. Charlie sees a Minion in a reflection. Agent Simons explains that he didn't imagine it, & that the United States of America... In fact, their very planet Earth, has been invaded by creatures from another dimension that want to take away their rights & destroy their way of life, but with that Deck, him & a very select group of other dedicated young men & women can help defeat them. Charlie says yes, it would be an honor to serve his country. Agent Simons says, "Welcome aboard."
Gallantmon reveals to Depthmon that he is human & that his name is Kurt Matsuki. But Depthmon still believes that Kurt is an alien & explains that Agent Simons told him about their tricks. Depthmon grabs Kurt, but then they see Beelzemon & Andromon fighting. Beelzemon has Andromon down, but Beelzemon can't bring himself to finish him. Andromon explains that he just wants his life back, then escapes. Depthmon attacks Beelzemon & uses "Swing Vent" (with 2,000 Attack Points). Gallantmon explains to Beelzemon that he's not a bad guy. With his bad luck becoming too intense, Depthmon has no choice but to listen to what they have to say.
At Murmuxmon's lair, Daniel is confronted by Murmuxmon that he knows he's planning to take out Murmuxmon. Then Murmuxmon, Justimon & Minions ambush him, but Daniel manages to escape. Justimon Rides after Daniel, but Daniel gets away.
Back at Kurt's place, Kurt & Mako try to convince Charlie that he has been lied to, but Charlie continues to believe that they're just trying to trick him. Morgan comes to the door, then Charlie makes his escape. Kurt & Mako split up to search for up. Mako finds him & tries to get him to listen, but Charlie transforms to Depthmon & attacks him. Depthmon uses "Copy Vent" & replicates Beelzemon's weapon, then uses Final Vent. Depthmon jumps onto Mantaraymon to use like a surfboard, & rams into Beelzemon, but Beelzemon survives the attack. Depthmon's bad luck becomes too intense for him to continue fighting. Beelzemon uses his Final Vent, but stops in mid-air. Mako then walks off.
Ben watches his last race & says to himself again, "Ben Shioda always wins!"