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.

Mari meets up with an unexpected guest of Alessandro Volta and learns a little more about her father's whereabouts.

Waka's wish to travel back in time is granted, but things don't go quite the way she had planned.

While Waka is still stuck in 19th century London, she learns a valuable lesson about dedication and overcoming failure.