Unlike his younger brother Isami, Katsumi is afraid of the tremendous power he has received since becoming and Ultraman. These two brothers will both have conflicting opinions about their newfound abilities. Their younger sister Asahi though tries her best to cheer them up and make them feel happy again. When all of a sudden another kaiju appears rampaging through the city, Isami gets buried beneath the rubble of the attack, and cannot move!
ウルトラマンになる力を得て有頂天になる弟・イサミに反して、兄のカツミは手にした力の大きさを恐れていた。真っ向から意見がぶつかる兄弟。その妹のアサヒは、「ハッピー♪」を口ぐせに、持ち前の明るさとアメ玉で兄たちに癒しをもたらす。そんな彼らの前にまたもや怪獣が出現！イサミはガレキの下敷きになり、動くことができない！
