“It’s pretty simple, Cass,” Cadence was explaining, sprawled out on one of the beds in the hotel room she would share with her sister for as long as they were in Philly. “You just stand there between Elliott and Jamie. If either one of them has to come help, you glue yourself to the other one. If both of them come to help, then you switch to Cale or Scarlet, the Healer from Philly. That’s it. You just stand there.”

Cassidy sighed. She was pacing the room, doing her best to convince her sister that she needed to be more involved, but so far Cadence wasn’t buying it. She wasn’t...