The Chromatic Void - Book 1 (The Heavy Black Door). Young Adults, #1

"Maya. It's all black, Maya... Except for the corner. I found the corner. Don't come looking..." For a year, seventeen-year-old Maya has listened to her missing brother's final voicemail . For a year, she has watched her mother fade into a ghost of grief. Now, she's done waiting. Tonight, Maya and local urban-explorer Jonas Hartley are climbing Obsidian Hill . Their target: Blackwood Manor, a brutal, light-absorbing fortress that the town of Oakhaven pretends doesn't exist .
But getting inside is the easy part. Trapped in a labyrinth of impossible architecture where the floorboards warp and the temperature plummets to absolute zero , Maya and Jonas must navigate by the faint, desperate clues Leo left behind . The deeper they go, the stronger the pulse of the house becomes-a heartbeat not of flesh and blood, but of pure, contained energy. In the absolute center of the Void sits a tall, black cupboard.
What lies inside is not darkness, but an explosion of blinding, chaotic color -and an ancient, predatory entity that is finally waking up. The hunt has begun.