Mark is a self-confessed dork of a rodent, who often acts out hyperactively but has more to him than the spazzy exterior he usually indulges in. Having been separated from his immediate family, he was taken in by his kind uncle Frank, who owned a bar and raised him well there. Later at this same bar Mark met a trio of other hamsters, Gwenendale Griggs, Oswald Irving, and last of all Tracy Starr, who felt strongly on equality. Mark found this interesting, and became friends with them, in time teaching Tracy to play piano and joining and helping to name their band, HamstaPowah.
Story Summary (Spoilers Beyond This Point)
Mark is running late to prepare for the band's last concert of the year, which has him afraid he'll get chewed out, but turns out to be a stroke of luck as he sees J'Aime Beck outside the entrance. Recognising the band's biggest fan, he lets her come in with him and they go to see the band's manager, Snowbell Crystal. J'Aime asks Snowy to find some way to let her friends in, since one of them, Samuel Boyd, spent most of their ticket money freeing some abused mice slaves. During the discussion it turns out they have a Tomedian with them (Hiaté Noumou). On hearing this Mark is stunned, and he tells Snowy they have to get them in, as no one ever leaves Tomed.
Snowy manages to get J'Aime and the others work backstage, and the band play their final show of the year, Mark fulfilling his usual role as DJ. The concert goes well, although at one point a young mouse breaks into the building on the run. The band sympathise with the boy, and Mark blinds one of the rat guards chasing him, buying Darin some time. The band eventually get him to stop running, but Mark notices something amiss, finding a number tattooed on his shoulder, indicating he's from a human laboratory. His bandmate Tracy rebukes him and says not to frighten the poor little boy, and despite his worries that the mouse could be dangerous, the others want to help and Tracy decides to adopt him, naming him Darin Starr as he appears to be mute.
After the show, the band are on their way back to their out of town residence, riding atop their cat Bobo, when a strange robotic machine attacks them. Bobo is stunned by an electrical attack and everyone else is sent flying. The robot tries to capture Sarai Kerice, who along with her mother Kamilia Kerice the band accepted as paid workers after Sam freed them. Darin however intercepts it, demonstrating an odd power.
Despite his impressive resistance Darin is overwhelmed by the machine, but the time he bought allows Mark to rally Bobo and attack the robot's central eye, destroying it. Mark recovers a shard of its circuitry with a strange symbol on it, and suggests they get going in case there are more than one of these things are roaming around. Later at the band's house, Mark talks to Snowy about the attack, being serious for a change as he explains how the symbol on the circuit he found could indicate that it came from a lab, and saying it could be tied to reports of a mouse changed to how rodents used to be that was found a while ago, as illegal lab work was suspected. They wonder if Darin might have an unusual resistance to the process since he isn't nearly as reverted as the mouse on the news, and if it was tied to the strange mark on his forehead, which appeared to glow when he used his power.
Although Mark wants to work out who is behind the attack, they don't have enough information to figure anything else out at present. Later, while doing errands in Crosond, the city is attacked by a whole army of robots like the ones they encountered. Aside from Snowy, the band mostly manages to stay out of the way of the danger, although Mark shows up in the closing stages with Bobo, having recovered Darin, who had been thrown out of the destruction of the lead robot that he caused.
With the attack thwarted, the band again returns to their house, only to hear later on the news that an explosion of unknown cause has wiped out a part of the red district of the city, causing them to worry for their friends, who they fear were involved. Darin is still recovering, and when Sarai goes to check on him, she ends up following him to the roof, where Darin has drawn an immense symbol in chalk. Sarai follows him into it and is transported to a strange realm as the rest of the band shows up. Sarai sees memories of his life, showing her his past and what happened inside of the command robot, which is also displayed to the band in the pillar of light now rising from the symbol. Mark and the others see the human scientist who claimed responsibility for the attack, Darin's condition, and a plan to revert the non-human species, allowing them to piece together far more of the puzzle. Lastly, Darin appears lucidly, asking for their help stopping him, before passing out again in exhaustion.
As the others turn in after the draining day, Mark communicates with an unknown ally using his computer, going by the name Jovial Commander as his contact Simply Steffani fills him in further on the scientist they saw, Doctor Lentle. 'SS' informs him that Lentle is unaware of how rare Darin's resistance to reversion is, and worries that it's may be the only thing holding him back from proceeding further in his plans to try and restore humanity to dominance. As far as Mark is concerned not a lot has changed in regards to Darin, as they still intend to protect him, but he realizes a plan to stop Lentle has to be devised as SS signs off to report back to their boss.