The magazine gives a short explanation of the story.
An Earth where peace has arrived. However, remnants of Frieza's army Sorbet and Tagoma (from the Japanese word for 'egg') arrive on the planet. Their goal is to revive Frieza with the dragon balls. Their dastardly wish is granted, the "F" that plans its revenge against the Saiyans is revived...!
Also 2 new characters designed by Akira Toriyama are revealed Sorbet (left) and Tagoma (right). They are what remains of the Frieza army and they will stop at nothing to bring their Master back.
via Anime News Network