Shadowhunter siblings

Okay, this is the sequel to Ever After. This will be about Clary and Jace's kids, Sofia and Jackson. These two twins are born minutes apart on Christmas Eve and are giving Jace plenty of time in training them and Clary plenty of time teaching them how to give runes and paint. Sofia is a daddy's girl and Jackson is a mamas boy...but what happens when a familiar face appears and takes their parents? What will Sofia and Jackson, age 16 do to save their parents? What has all their training taught them and how will they use it?