During the Battle at the PRIDE Construction Site, PRIDE and the Runaways worked together to destroy the Magistrate's Ship so that he could not leave Earth and cause catastrophic earthquakes. The ship's destruction allowed the Magistrate's wife, daughter, and son to escape the ship, as well as a Xartan named Xavin. Soon after, Nico Minoru used the Staff of One to kill the Magistrate's host body. While Xavin escaped, the Magistrate and his family possessed Victor Stein, Stacey Yorkes, Tina Minoru, and Alex Wilder, respectively. While The Magistrate, his wife, and his daughter revealed themselves during the Chase of the Runaways, the son kept his identity secret.
While Alex Wilder talked to his mother, Catherine, and Leslie Dean rested, Karolina Dean, Gert Yorkes, Molly Hernandez, Nico Minoru, and Xavin went to the Minoru Mansion in order to get more Inhibitor Pods, so they could determine which one of them was the Magistrate's Son. After recovering the technology, Yorkes insisted that they wait to all take the test at the same time. However, the group was fighting, so they took it in a public park where no-one could kill anybody, and determined that none of them were the Magistrate's son, meaning it must have been either Wilder or Leslie.
The Runaways returned to the Hostel in order to give Leslie and Wilder the test, but both were missing, so Stein checked the security WizCam he set up, and discovered that the Magistrate's son had possessed Wilder and taken Leslie.
The Magistrate's Son stopped at Randy's Donuts and called his father, offering him Leslie Dean's unborn child in return for his own freedom. The Magistrate accepted the offer, and his son killed the clerk in the donut store for fun as he took the donuts. Dean's water broke, and the Magistrate's son took her to Tamar's house, since the hospital would take too long.
Leslie told Tamar that she didn't trust Wilder, so she had Tamar call text Karolina Dean and tell her where she was. Chase Stein and Gert Yorkes created weapons which could be used to kill a Gibborim, and they went to Tamar's house. While the Magistrate's son attempted to kill Tamar, the Runaways showed up, resulting in a chase between him, Nico Minoru, and Karolina. Minoru cornered him, but the son manipulated her into letting him go.
With Leslie Dean having successfully given birth to Elle, Xavin got a hold of the Abstract from the Magistrate's Son, and noticed that the Magistrate's family sent a beacon to their home planet, which will result in their return home and the arrival of a Scrub Squad to kill all humans who have had contact with the Magistrate and his family.