Dragon Ball Z Kai Season 3 Episode 15

Bulma receives a phone call about one of her company’s products from Capsule Corporation. She is sent a photograph of what appears to be Trunks’ time machine that he travelled in. Trunks investigates this with the others only to discover that it is the exact time machine that he came in but three years later in his world. He recognizes it because of the word ’Hope’ that Bulma wrote on the time machine. Kami realizes that the evil he felt four years ago wasn’t the androids but it was the monster that travelled back in the time machine.