Diving into a rich palette of synth-pop hooks and smoldering balladry, former Led Zeppelin frontman Robert Plant aims for a fresh new sound on his fourth solo album. His expressive croon mixes beautifully with the Depeche Mode-style electronic pulse of “Heaven Knows.” He’s utterly seductive on “Ship of Fools,” his voice floating on a bed of synths and big ’80s drums, while “Tall Cool One” is a sampladelic rock jam featuring Jimmy Page on guitar.