The supernatural is weak mortar to fill cracks in a film’s plot. That being said, everything else about “The Black Phone” (2022) is so stylishly done, I’ll grant some willing suspension of disbelief. This low-ceiling horror film leans into its late 1970s Denver setting, so much so it sometimes seems the set decorator and costumer are bragging. Meanwhile, kids are disappearing. The Grabber gains schoolyard-myth status as the suspect. Our protagonist is in the crosshairs. Earnestly sold clairvoyance and paranormal activity begin to intervene, but young heroes Madeleine McGraw and Mason Thames prevent the story’s potential undoing through heartfelt performances.