Boxer was an ex-British Special Forces soldier who was working as a bodyguard to Gwen Murakami: the daughter of a Japanese billionaire, when Godzilla re-emerged in Washington D.C. after the events of Godzilla: Kingdom of Monsters, in which Boxer lost his daughter. As Godzilla drew nearer, Boxer took the girl he was guarding out of the crumbling building by various means, but their final escape was made by sliding down a rope in a half-exposed elevator shaft and landing in a tree. They were then approached by some United States Military, who urged them to flee, but they then ran into a militia who claimed that the U.S. Government had declared D.C. a total loss and were pulling operations to stop Godzilla's attack. When the militia saw Godzilla behind Boxer and Gwen, Gwen was killed in the crossfire. Boxer tried to take her to her mother at the United States Capitol building, but Godzilla destroyed it and her body is lost. Boxer then decided to assemble a team to stop Godzilla.
After being nearly killed by Anguirus in Edinburgh, Scotland, Claire Plangman's "Skullsplitter" device wass destroyed when Anguirus ran into their van. she was able to repair it, and Boxer fired the weapon at the monster and kept it in the beam long enough for Urv to set off plastic explosives in the sewers, and forcing Anguirus into a dormant volcano beneath the city. during an interview after Anguirus' defeat, Boxer demanded seven billion dollars for each monster they kill, which Boxer reasoned was a reasonable amount, as it was one dollar for every perso on the planet. They then become known as the Monster Kill Crew. Later in Taos, New Mexico, the group set off a rock-slide and crushed Kumonga. Much to Boxer's dismay, in Sao Paulo, Brazil, he was unable to defeat Rodan because Harrison did not maneuver their vehicle to keep him sedated and send him into an electrified net. They then defeated Battra in Seoul, South Korea, and Boxer suggested that they try to go after Godzilla in Saint Louis, Missouri. To Boxer's disdain, they instead headed for Tokyo to conquer Titanosaurus, but were attacked by Rodan en route.