Matthew Daddario (Delivery Man) and Isaiah Mustafa (Horrible Bosses) are the latest to join the cast of Shadowhunters, ABC Family’s straight-to-series drama based on the bestselling young adult fantasy book series The Mortal Instruments by Cassandra Clare.

The series, whose first episode is directed by McG, follows 18-year-old Clary Fray (Katherine McNamara) who finds out on her birthday that she is not who she thinks she is, but rather comes from a long line of Shadowhunters — human-angel hybrids who hunt down demons. When her mother Jocelyn is kidnapped, Clary is thrown into the world of demon hunting with mysterious Shadowhunter Jace (Dominic Sherwood) and her best friend Simon (Alberto Rosende). Now living among faeries, warlocks, vampires and werewolves, Clary begins a journey of self-discovery as she learns more about her past and what her future may hold.

Daddario will play Alec Lightwood, who joins Jace and his sister, Isabelle (Emeraude Toubia), in their pursuit of demonic creatures. He’s tortured by his romantic love for Jace, who is his adoptive brother and fighting partner. The eldest of the group, his strict moral code forces him to follow the law to the letter. Mustafa is Luke Garroway, an NYPD detective investigating a string of “demonic” murders. Luke feels a fatherly instinct to protect Clary, a strong affection for Jocelyn and has secrets of his own. Once a strong and powerful Shadowhunter, he has since become the thing he once hated most – a werewolf pack leader.

Shadowhunters is produced by Constantin Film and executive produced by Ed Decter and McG.