Dragon Ball Z Special 2: Zetsubou e no Hankou!! Nokosareta Chousenshi - Gohan to Trunks  

Dragon Ball Z Special 2: The History of Trunks, ドラゴンボールＺ・絶望への反抗！！残された超戦士・悟飯とトランク, Dragon Ball Z: Trunks historie, Dragon Ball Z: Trunks historia

For thirteen years, the Androids have been wreaking havoc, with only Son Gohan standing up against them. As his mentor, he takes Bulma's son Trunks under his wing and sacrifices himself to protect him. Now it falls upon Trunks to alter this disastrous course of events.