EMMA AND HOOK ARE PULLED INTO ZELENA'S TIME PORTAL AND FIND THEMSELVES IN THE ENCHANTED FOREST OF THE PAST - BUT THEY MUST BE CAREFUL NOT TO CHANGE ANYTHING OR RISK ALTERING THE LIVES OF THEIR FRIENDS AND FAMILY, AS WELL AS THEIR VERY OWN EXISTENCE, ON THE TWO-HOUR SEASON FINALE OF ABC'S "ONCE UPON A TIME"

"Snow Drifts"/"There's No Place Like Home" - While Mary Margaret and David celebrate the naming of their son at a coronation in Granny's Diner, Emma and Hook are pulled into Zelena's time portal and find themselves in the Enchanted Forest of the past. But in their quest to discover a way back, they must be careful not to change ANYTHING or risk altering the lives of their friends and family -- as well as their very own existence.