S1OVA1 Makoto's Problem!

Makoto's Problem! (真琴の悩み！Makoto no Nayami!) is the first original unaired short movie that came with Free! vol.1, which was released on September 11, 2013.

Synopsis
Makoto Tachibana reveals to Nagisa Hazuki that he has great problems with Haruka Nanase stripping all the time. As he explains, he went out shopping with Haru the day before and Haru, upon spotting a large fish tank, left Makoto behind to strip and try to get inside. When stopped, Haru always becomes irritated. To discover why Haru behaves this way, Nagisa decides that they should conduct an experiment.

First, Makoto cups his hands together and holds a bit of water in his palms. Haru walks back, stares at the water, then scoffs as he turns and walks away again. Second, Makoto and Nagisa try a basin filled with water which catches Haru's attention and even causes him to look back at it as he walks away. Third, the two experiment with a bucket and Haru stares at it long and hard, causing Nagisa to comment that he looks like he is suffering. Fourth, a tub was used and this time Haru nearly undoes his tie; however, at the last second he decides against it. Finally, Makoto blows up a small children's pool while Nagisa fills it with water, but before the two of them can finish putting the pool together, Haru spots them from afar, strips, then quickly runs and jumps into the water.

Drenched, Makoto and Nagisa finally understand Haru needs enough water for his body to be submerged in before he will strip down.

Characters
List of characters in order of appearance:

Trivia

 * Prior to Free!'s English DVD release by Funimation the episode was called 'Makoto's Trouble!' in English