Lotta loves April 1st; Daisy Town dreads it because of her April Fools pranks. Luck is summoned to the tent of a visiting Russian prince, and lets Lotta come along. The Prince appoints Luke as his bodyguard and takes great interest in Lotta. Trouble starts when the Prince and his fianc?(who is jealous of Lotta) fight. The Prince declares that he'll marry Lotta instead. The Princess declares that she too will marry a "commoner," Lucky Luke! When Luke declines the offer, the Prince challenges Luke to a duel, and Lotta withdraws her acceptance of marriage - but both are sentenced to death! Just before they are beheaded, Luke turns to Lotta and says, "April Fools!" The Russians are hired actors. Lotta vows to get even with Luke!