Explorers in the 1930s journey to a remote, uncharted island in the Atlantic ocean, searching of a missing team of British archaeologists. A mysterious order of knights wants to stop them, however, and the island natives don’t seem too welcoming either.

Willow Pipp, Simon Maker, Fennel Wispywhisks, and Squeaky McSquirmels face off against the wicked Princess Maybelline, attempting to secure the Staff of Suetonius from its crystal cocoon. Afterwards, once again mounted on Sir Snuffles, they journey to the Northern Marches, where Lord Balthazar and his Pierats dwell in the city of Chimneyhaus. An epic battle ensues, and the lowly mice of Bernpyle must rise to the occasion and prove they truly belong among the renowned ranks of the Mausritter.  

Riding on the back of Sir Snuffles, the mice enter the realm of the Faeries in search of the Staff of Suetonius. Once there, they immediately find themselves entangled in royal intrigue and must fight to free Queen L’Oréal from imprisonment at the hands of her usurper, Princess Maybelline.

Leaving Bernpyle once again, the mice head west to the land of the giants, in search of a corgi to aid them in their inevitable battle with the cat, Lord Balthazar. The trip presents a new threat in the form of crustaceans, and later, an unexpected ally protects the rodents from a plethora of predators.

With the missing cheese in tow, the mice head back to Bernpyle, taking the rescued Stumpsville residents and a captured Pierat with them. Along the way, the hairy heroes suffer a terrifying assault from above and meet another furry fellow whose wise words alter the course of their mission.   

The mice investigate the invaded city of Stumpsville and face off against savage Pierats and killer spiders, rescuing some of the residents. The key to saving their precious cheese, it turns out, might be connected to the sweet sound of music.  

Four little mice who live in the city of Bernpyle are sent on a crucial quest to find out why a delivery of cheese from the city of Stumpsville never arrived. As they undertake their arduous journey, an encounter with ruthless frog bandits tests their courage, but the furry foursome endure, reaching their destination and discovering yet another danger: dreaded Pierats!

The team rescues a civilian and servitor carrying vital intel from the crosshairs of a sniper, then helps secure the area. Things turn chaotic when the lights suddenly go out just as a horde of Poxwalkers shows up. Will it be lights-out permanently for Kroog, Flak, Lynane, and Bumper, or will they shine brightly like the flame of the emperor?

The heroes are faced with escorting a Fireteam Bravo tank through the rubble and helping the wounded that are strewn across the battlefield. Afterwards, tanks and Valkyries bombard the spire and its gates, while the ground soldiers push forward. Finally breaching the gates, the team confronts a formidable cultist.   

After taking shelter and awaiting their next orders, Kroog, Flak, Lynane, and Bumper are tasked with disarming mines to clear the way for tanks as they proceed to Delta 9. Explosions occur. Later, the team meets a suspicious man claiming to have disturbing news about the emperor.