I reading "BACK TO THE FUTURE". it was published 1998 by screen play company.

Main character is Marty and his perents.

If his perents do not kiss, Marty disappears.

Marty succeeded that insure kiss. He didn't disappeareas in this world.

Various happning,he can come back to the future.

Marty went to wait place with the Doc.

unless ～でない限り
Unless you know somebody else that can play the guiter.

fool 愚か者
I'm just a fool.

run into偶然　ばったり
Marty walks off stage and runs into Lorraine and George.

go easy onお手柔らかに
go easy on him

accidentally偶然に、故意でなく
accidentally sets fire to the living room rug