Spark returns us to the spaceship Empyrean right where Glow finished off, a crew full of kids is piloting a ship chasing after their parents who are imprisoned on another spaceship, the New Horizon. In a race to save their parents but also to finalize their own animosity towards their previous captors, the Empyrean is increasing its ship's speed at the cost to the health and well being of the young crew. Waverly, a girl who was kidnapped and then fled New Horizon finds her return to the Empyrean full of strife and a whole host of complicated feeling from the crew. Kieran, Waverly's previous boyfriend, is acting as Captain of the Empyrean and leads inspirational talks to the crew but finds his attendance to his new sermons and leadership lacking fervor. With Kieran’s crew's moral weakening, this soon turns Spark into the story of a race towards power among the occupants in the ship just as they are being attacked from within the Empyrean by an unknown person or group.
With Waverly lost in her own thoughts and Kieran turning power mad when sabotage and strange occurrences begin happening on the ship, death and danger fast approaches. Being young and in charge of hundreds of kids can make a monster out of anyone when pressure mounts and kids are dying, but true power has to be earned and can have drastic consequences. As Kieran is hiding transmissions from the Empyrean with his contact with the other ship New Horizon tension mounts and there may be a mutiny happening.
Spark is a breathtaking interstellar journey about the harrowing times of being young on a spaceship racing against all odds to get to a new habitable planet and saving parents from a rival ship. Layered in a history of suffering and deceit, these two ships are vying for their own agenda through the space sea of time, and time is running out through their own attacks. The series is led mainly through the eyes of two teens, Waverly and Kieran and through their eyes we bear witness through a whole host of trials and tribulations of being young and in charger through death and devastation.