The Vamps faced 2017’s changing pop scene with a big idea. Night & Day is the first part of a twin album, which tells the story of a wild night out, using the dynamics and sounds of club life. “Middle of the Night” puts the band’s pleading harmonies to dubstep dynamics, while “Hands” and “It’s a Lie” use the loping swing of tropical house. But the softer, guitar-led “Paper Hearts” and “Stay” prove they will return to impassioned pop-rock when the emotional chips are down.