What is that movie called?

ok well it came out 2 maybe 3yrs ago, its about this boy and he meets this girl who is his nxt door neighbour, they go out on this adventure into the forest and find a magical land sort of thing they then go there every afternoon and fight off all these creatures at the end the grl dies trying to cross the creek. PLEASE help i am trying to remember the name and i cant, its driving me crazy!!!!