The royal family of Atlantis are enjoying some down time, outside the city's walls. Aqualad, his sea horse, Imp, Tusky, a walrus, and the infant, Arthur, Jr., are playfully roughhousing, to Aquaman's great amusement, and Mera's great concern. Mera's fears come to fruition when Arthur, Jr.'s life is suddenly placed in jeopardy. Too forcefully bucked from Imp's back, the tiny heir of Atlantis is sent hurtling towards an outcropping of rocks. Before anyone can react, Arthur, Jr. is saved by Aquaman's evil half-brother, the Ocean Master. Aquaman and Aqualad demand Ocean Master release the Prince of Atlantis. Ocean Master responds by callously tossing the baby away. Mera projects a hard water hand to catch her son. Furious, it's all Aquaman can do to stay his hand from striking his half-brother