Raul and His Vampire Prince Vol 2

From the Seven Seas Entertainment edition

SIPS THAT BRING SLEEP Rosé, an eternally youthful vampire, has received an invitation from human royalty. His escort will be none other than a prince, and it promises to be a glamorous evening. But instead of drinks with high society, Rosé ends up drugged and unconscious. It will be up to his stalwart servant Raul to rescue him!

Source: Penguin Random House API