"Finding Dory" is about sleep-swimming

Disney-Pixar's "Finding Dory" , the sequel to animated sea adventure "Finding Nemo", is about sleep-swimming.
Forgetful Dory, voiced by Ellen DeGeneres, with her friends Nemo and Marlin (Albert Brooks) are on a search for answers about Dory's past, reported Deadline.
What can she remember, who are her parents and where did she learn to speak Whale, are some of the questions this movie explores.
This is all evidently triggered by a case of sleep-swimming as seen in the first trailer.
Pixar's John Lasseter presented footage of the movie in Cannes where he said, "Where is Dory's family? That has been just bugging us since we made (Finding Nemo) and we thought this could be a great place to move forward."

Andrew Stanton returns to direct with Diane Keaton and Eugene Levy voicing Dory's parents, and Ed O'Neill as Hank the Octopus.
A new addition to the film are the Loons, who do not appear in this first teaser, but to whom Lasseter referred as 'the Seagulls' of "Finding Dory".
"They're so startlingly dumb it's hilarious," he said.