The Makers are invited to compete in a local STEM fair, which has prizes for the top presenting schools. Maker Sadie desperately wants to beat the team from nearby Skillby Tech. Inspired by a local sanitation workers' strike, Sadie decides to create a series of junkbots using her school's new 3-D printer. However, she comes to school to find that the printer has been sabotaged...or has it? Sadie is devastated and suspects the team from Skillby Tech...