Atthestartofhighschool,Piper,Sophie,IsabellaandHonorthinktheywillbebestfriendsforever,sotheysinkatimecapsuleinthelakewithalistofthingstheywanttodobeforegraduation.Bysenioryear,theyhavegonetheirseparateways.Piperhasturnedintotheclassclown,partygirlwhoneverpassesupadrink.Sophiepledgestostayavirginuntilsheismarriedandhascreatedapurityapp.Is abellaisthefeministfemmefatalewho'stheeditorofazine.AndHonoristheprideandjoyofthecommunity.Herdreamofbeingaprofessionalballerinaistakingoff.Butwhentragedystrikes,theformerBFFsmustreunite,breakopenthecapsuleandcompletethepre-graduationbucketlist.