Dragon Ball Super S04E03 - A Message from the Future Goku Black Invades!

Goku holds Future Trunks off long enough for Bulma to calm him down, Future Trunks is formally introduced to everyone present while being informed of the events that occurred since the Cell incident. Future Trunks reveals that after he prevented the revival of his timeline's Majin Buu, Goku Black appeared and massacred most of humanity with only him and few remaining people fighting him in a losing battle. Bulma deduces that Future Trunks came back in time to get reinforcements while finding a journal that her future self hid in the Time Capsule, Goku and Vegeta both intrigued while Beerus and Whis are astonished that humans are bold enough to mess with the affairs of time-space. Back in the alternate future, Black realizes Trunks traveled back in time as he uses his ring to open a tear in time to reaches the present as Future Trunks finished his spar with Super Saiyan 3 Goku to determine each other's power.