Dragon Ball Z (dub) Episode 121 -

In the English dub of Dragon Ball Z, episode 121, titled "Welcome Back Goku," the mysterious Trunks reveals himself as the son of Vegeta and Bulma from a post-apocalyptic future. Trunks warns Goku of an impending heart virus and the arrival of murderous Androids, providing a future antidote to ensure Goku survives to lead the fight.