Maralys has a rival at school, and it's getting under her skin. Susan Ashby's father owns a technology company, and Susan uses that to her advantage during a class presentation. Maralys decides to show Susan how to do things Maker Club style. After a hectic trial-and-error period involving tea and lemon juice, not to mention a ton of pennies, Maralys assembles her own battery. How will her battery perform for the class presentation? Will Susan Ashby have the last laugh? Curious readers find the answers to these questions in the pages of this exciting and humorous narrative.