Lady in the Water (2006)

A modest building manager named Cleveland Heep rescues a mysterious young woman from danger and discovers she is actually a narf, a character from a bedtime story who is trying to make the treacherous journey from our world back to hers. Cleveland and his fellow tenants start to realise that they are also characters in this bedtime story. As Cleveland falls deeper and deeper in love with the woman, he works together with the tenants to protect his new fragile friend from the deadly creatures that reside in this fable and are determined to prevent her from returning home.

Official website: http://ladyinthewater.warnerbros.com/