" Sam's phone buzzed. She fished it out of her pocket, checked the screen, and cursed. " I have to go." " You just got here." " Valkyrie business. Possible code three-eight-one: heroic death in progress." " You're making that up." " I'm not." " So...what, somebody thinks they're about to die and they text you 'Going down! Need Valkyrie ASAP!' followed by a bunch of sad-face emojis? "