When Supergirl came down to Atlantis, he volunteered to show her around, quickly becoming enamored of her. After she defeated a series of ancient weapons accidentally let loose on Atlantis, Jerro told her she was lovely. During a celebratory pageant held in her honor, Jerro competed in a race. The two prizes for the winner were a trophy and a kiss from Supergirl. Jerro won, and Supergirl kissed him. Supergirl, herself becoming enamored of Jerro, quickly left Atlantis when she realized the Atlanteans were privy to her thoughts during and after the kiss, despite Jerro's asking her to stay longer. ("Supergirl's First Romance!")