Being Drifted, Message Bottle
While Suzu was collecting seaweed by the coast, a bottle drifts ashore. Upon looking at it, she immediately presumed that it was the bottle that Ikuto had sent to his sister Misaki. She came back home to show it to Ikuto, and while reading the letter, it read that his sister went off to the sea to try to find Ikuto, but has gotten lost; therefore, Ikuto, Suzu and the other girls attempt different ways to get Ikuto out of the island to find Misaki.
Aired 13/09/2007EP 24 - Being Drifted, Message Bottle

Nagasarete Airanto
After a terrible argument with his father, Ikuto makes a hasty, fateful decision to run away from home. Going from runaway to stowaway, Ikuto’s luck lands him on a ship heading right into the path of a huge storm! When it rains, it pours — or in Ikuto’s case, it pours so badly that he washes overboard and wakes up on a deserted island. Well, an almost deserted island. The island is populated by nothing but beautiful girls, all of whom want Ikuto to choose them as his bride.
(Source: HIDIVE)