April's downfall. 

This is essentially Clementine & Jesse' backstory,how their best friend was killed in an accident & they had to leave.Since April was dying,they had to find someone else to become friends with,otherwise they would die.
Since Clementine & Jesse are "imaginary friends",their life force comes from living people.They attach themselves to someone,using them as a source of survival,& in return,they become friends with that person.
I will eventually explain how they meet Tinsel & the others,but for now,this is it!
I hope you like it!