Sea Search is a quest found in Epic Mickey: Power of Illusion. It is given to Mickey by Ariel straight after she opens her room.
Ariel will ask Mickey if he knows anyone that can help fill her room with treasures. To complete the quest, Mickey must go to Donald Duck's Room, and Donald will soon be persuaded to help out.
After Mickey heads back with Donald, the quest will be completed and Ariel will reward Mickey with a Health Upgrade and a Room Star.