The story is a pseudo-sequel to the Lion-Force-based subset of original 1980's series. The premise places it some years after the conclusion of the old series' first season, but certain historical events revealed in the new series demonstrate that Voltron Force's back story has significant differences than that portrayed in the classic series.
After the defeat of King Lotor, the galaxy settled into peace. During a celebration, the Voltron lions went haywire. Sky Marshall Wade, head of the Galaxy Garrison, ordered the lions decommissioned, and the Voltron Force dispersed. Lance, Pidge, and Hunk took positions within the Garrison, while Princess Allura returned to Arus. Keith, however, has disappeared. Under Wade's leadership, the Garrison has grown authoritarian. Meanwhile, Zarkon's son Lotor, once thought dead, has been revived and taken his father's mantle as the new king of Doom's forces.
But the former members of the Voltron Force have not given up the fight! With the help of the cadets Daniel, Vince, and Allura's niece Larmina, they will reunite to get the lions back and Voltron will defend the universe once more!