Trunks has killed Cell, and lived a quiet life for about 12 years (currently 29 but Saiyans stay in youth longer). Ine day he decides to visit his alternate timeline.
When he arrives to the past he sees all his friends older and much stronger (5 years after the battle with Boo). Gohan and Krillin tell him all that has happened. Trunks is shocked, Goku tells him about SSJ 3.
Trunks asks for hard training so he can defend his future in case of any threats. Goku allows him to train with his younger self in the Hyperbolic Time Chamber.
Trunks looks strikingly different than his young counterpart. His hair is thick and goes down to his shoulders. He is about 6'6 and very muscular. He still has his sword that Tapion gae him.
The younger Trunks trains with him. Trunks returns back to the future, gathers the dragon balls (he got the radar from the past). Shenglong arises and grants the wish of "Resurect everyone killed by the androids".
Shenglong dissapears and Trunks starts to weep, as he feels a hand on his shoulder, he starts glowing. It was Son Gohan!!!!! Gohan goes to his house and sees all is old friends. But then he hears a maniacal laugh. DR. GERO!!! He was killed by the androids too!
Gero dissapears and Trunks laughs and thinks we can handle him. Trunks and crew (all the Z fighters and co.) go to the alternate timeline to see all their couterparts. OUR Z fighters are about 100x stronger. They all enjoy being alive and party. But when they return they make a horrorfying discovery....