New York institute gets an unexpected visit from Rafael Lightwood-Bane, the adoptive son of Alec Lightwood and Magnus Bane. Except it's year 2018 and Magnus and Alec haven't adopted him yet. Rafael was sent by the Clave to the past to warn Shadowhunters about a demon attack that could potentially put the Mortal Cup in danger. So you can imagine everyone's surprise when they learn Magnus and Alec have a son in the future.