When the world needs a powerful witch arrested, a demon monster evicted, or a cursed truck to be towed, who do they call? The Guardians, protectors of mankind. Lead by world renowned spy, Kim Possible, she commands a team of super-powered teens, such as Ben Tennyson, who can transform into aliens, Danny Fenton, who can transform into a ghost, Zak Saturday, who can take control of cryptids, Jenny Wakeman, a robotic super-solider, and Elyon Brown, a stranded queen from another dimension. Together, they will rid the world of evil, protect the innocent, and solve the mystery of the Plague Doctors, the assaulters who stole Elyon's powers.
The unearthing of an alien device enabling instantaneous space travel creates a headache for U.N.I.T. when Brigadier Alastair Gordon Lethbridge-Stewart and an exploration team go through the portal...and don't come back. Meanwhile, decades later, U.N.I.T. General Yvette Dwonch and her research team come upon the same device, utilize its properties, and also fail to return. Now their fates lie in the hands of the two Time Lords who can solve this dilemma: Maureen (the fifteenth incarnation of Neas) and the third incarnation of her old mentor and friend, the Doctor.