Harry’s heart fluttered. He risked a glanced at Hermione’s face, which had paled

Harry and Hermione looked on helplessly as Wormtail approached them with a sharp, thin knife.

Harry drew a sharp breath, as Wormtail drew a thin line of blood.

Hermione tried to pull her arm away, but Wormtail dug his sharp claws into her arm as he grabbed it, and cut a small incision in her arm as well.

He handed the phials of blood to the Dark Lord, who then slowly and carefully allowed several drops to fall in the bubbling cauldron, that simmered over the crackling fire. 

It was only through years of self-discipline that Snape was able to retain his air of calmness, in the face of danger; if the Dark Lord found out who these children actually were—they would all be in serious trouble.

When, however, the Dark Lord’s thin lips curved into a smile, Snape’s dark eyes widened in surprise. He risked a look at Bella; she didn't seem nearly as surprised at the results as he was.

He narrowed his eyes suspiciously at her.