The old oak stood at the edge of Bob's backyard, its branches sprawling against a sky bruised purple with dusk. Bob pressed his palm flat against the bark, feeling the cool roughness under his fingers. The symbol was about the size of his hand — three intersecting arcs with a dot at the center, carved deep enough that the inner wood was still pale, still raw. Petunia sat at the base of the tree, her massive black chest rumbling with a low, steady growl. Her eyes didn't leave the carving. "You sure it's new?" Bob asked, not turning. Johnny Maverick stood a few feet back, guitar case in hand. He'd arrived without warning, engine cut before the driveway, footsteps soft on the gravel. Now he set the case down on the dry grass and flipped the latches. Bob heard the soft sigh of leather hinges. "Come here," Johnny said. Bob crossed the grass, Petunia padding beside him. Johnny had the case open, revealing a burst of purple velvet lining and a guitar that caught the last light like water. But he wasn't looking at the guitar. He was pointing at the back of the case — at the same three arcs and central dot, scratched into the leather, worn but unmistakable. "Who had this before you?" Bob asked. Johnny's jaw tightened. He took off his aviator sunglasses, folded them slowly, and tucked them into his jacket pocket. Without them, his eyes looked older. Tired. "Guy named Tobin. Lead guitarist in my first real band. We were eighteen, sleeping in a van, playing dives from Bakersfield to Spokane. He disappeared halfway through a tour. Took his gear, left this case behind. Never heard from him again." Bob looked from the case to the tree. Same symbol. Same precision. "What does it mean?" Johnny was quiet for a long moment. A train horn sounded somewhere in the valley, distant and lonesome. "I don't know. But I saw that symbol on a lot more than just this case. Tobin carved it everywhere — on walls, on his amp, on the back of a diner menu once. He said it was a door." "A door to where?" Petunia's growl deepened. Bob felt the hair on his arms stand up. Johnny looked at the tree, then at the boy beside him. "That's what I've been trying to figure out for twenty years." Behind them, the porch light flickered once. Twice. Then held steady. But the air had changed — charged, expectant, like the moment before a storm breaks. Bob reached into his pocket and pulled out a piece of paper. Unfolded it. Held it up beside the tree. It was a rubbing of the symbol he'd taken from the alley wall two nights ago — the one that glowed green under Petunia's nose. Exact match. "I think I know where the door is," Bob said. His voice was steady, but his hand shook just a little. "I just don't know how to open it." Petunia stopped growling. She turned her massive head and looked at Bob, then at the tree, then back at Bob. And then she did something she'd never done before — she pressed her wet nose to the center of the symbol and held it there. Tree bark began to glow.