After the battle with Frieza and Goku Black, things have returned to normal and Goku & Vegeta go back to training on Beerus's planet. At an inconvenient time too. Beerus has fallen into a heat and will seek out strong and suitable potential mates. His heat cancels out god Ki and as such Whis sends the two saiyans away. Or tries to. They refuses and our story begins there.