Young house mouse Chester has big dreams to follow in his grandfather's pawsteps as a midshipmouse at the prestigious Naval Mouse Academy.

But the notorious first year of training gets off to a rocky start when unexpected hurdles threaten to derail Chester and his band of rodents. No plebe mouse wants to be the weakest link, and Chester is determined to succeed. Unfortunately, his well-planned efforts are soon turned topsy turvy by a flotilla of dangerous foes, and one of them wants him gone.

As Chester strives to navigate the epic journey of plebe year, human midshipmen in the rooms below also pursue their own rigorous training. The parallel lives of mice and men spiral ever closer together until their worlds clash, creating far-reaching consequences. High standards of honor, courage, and commitment are put to the test. Will Chester risk it all to right a wrong?

Stretched to the limit, Chester questions whether his friendship with his shipmates, heaps of dry breakfast cereal, and the occasional butterscotch crumble will provide enough steam to keep them all going through the dark ages of plebe year-The Second Third.