大助はアパートで恋人の美果とセックスに明け暮れていた。そこへ少年時代の野球仲間ツトムがひょっこり訪ねてきた。彼が置き忘れた携帯電話を届けるため、2人はツトムが住む町へ向かうが、彼は8年前に事故で死んだという。道中出会った、かつての対戦相手・憲太郎とその恋人を含めた4人が途方に暮れていると、ツトムの携帯が鳴った…。Sex Friend Nurezakari is the story of an old friend, Tsutomu, who pays a visit to a couple then disappears after one night. He leaves behind a mobile phone and the couple set out to find him and return it. Along the way they meet up with another couple enjoying an outdoor sex session with a video camera. The four of them continue the journey to find Tsutomu. When they arrive at his home, his parents inform them that he was killed in an accident some years previously. What happens next is both bizarre and strangely heart warming as the four friends play a baseball game with the ghost of Tsutomu and thus seal their friendships for good as all of them discover more about themselves and each