札幌競馬で10勝して得た賞金を豪遊で使い果たした氷室翔は、その賞金を期待する妻･アブ美に真実を告白できず、今度のサファイアステークスで1着を取るしかないと考える。そんな時、札幌のホステス･タマコが栗東へやってきて動揺する氷室、そのうえサファイアステークスで騎乗する牝馬･ドサンコレディーが発情してダメになったと知らされて......!? Shou Hiromu has 10 straight wins in the Sapporo Horse Race and obtains the prize money but uses it all up on gambling. Being unable to tell this truth to his wife Abumi, who was expecting something nice from the money, he knew that he had to win 1st place in the upcoming Sapphire Stakes race. But the hostess Tamako comes to his work place which makes him restless, and not only that, the horse he planned to race with had suddenly goes into a state of estrus!?