Mari and Waka plan on making a cake for their friend, but plans fall apart when Mari opens a mysterious book that sends her flying back in time where she ends up crossing paths with William Gilbert.
Mari spends time with Dr. Gilbert while he hypothesizes about the Earth's magnetism. Meanwhile, Waka and her brother search Mr. Hayase's lab for signs of Mari.
An afternoon following a school lesson on Ben Franklin leads to Mari meeting the man himself, helping with the kite experiment, and discussing future appliance innovations.
A rift appears in space-time, trapping Mari, Mikage, and Dr. Hayase in Edison's warehouse. With Hayase's lab experiencing a meltdown, will the trio make it back to the future?
