I need you to steal a person

Adventurers met Alex Starkweather in a bar, and were tasked with retrieving the late king's illegitimate son, a ten year old named Arthur, and seeing him to a long forgotten royal safehouse. After he was picked up, the party was ambushed by persons unknown. The ambush was successfully repelled, and the party made it to the safehouse. The safehouse is clearly magical, and responded to Arthur.