Ever since the androids attacked and killed Krillin, Tien, Yamcha, Chiaotzu, Vegeta and Piccolo...Goku died of the heart virus before the Android 17 and Android 18 attacked...Now Gohan, Trunks and you are humanity's last hope since Gohan is training you and Trunks.

Gohan: "Good work you two. That was great but it's not enough to beat the androids. We need to get stronger."