Bubbles learns that every drop of ocean water is full of life, and decides to take in a nanoplankton friend who is invisible to everyone, including her. / Tidy meticulously cleans up the kelp forest in anticipation of the arrival of his new partner, a female garibaldi fish named Neat. Splash and his friends, however, get Mrs. Tidy mixed up with another fish, who's not an easy fit in the kelp forest. When the real Mrs. Tidy (Neat) arrives, she is very impressed with Tidy's clean algae bed, and appreciates the kelp forest.