FRANK CASTLE x OC | AGE GAP | DAD'S BEST FRIEND Sienna thought coming home would be temporary. At twenty-three, she has her own career, her own plans, and no intention of staying in the small town she spent years trying to leave behind. Then there's Frank Castle - her father's best friend and the man who lives right across the street. He's a former soldier with a failed marriage behind him, a small business of his own, and twenty years on her. He's been part of her life for as long as she can remember, making him the absolute last man she should ever look at differently. But somewhere between late nights on the porch, rides in his old pickup, lingering looks, and touches that last a little longer than they should, something changes. Sienna isn't a kid anymore, and Frank is starting to notice. He knows better, and she should too. Neither of them, however, seems particularly good at remembering that. ................................................... A slow burn, forbidden age gap romance inspired by Jon Bernthal's Frank Castle. (Frank Castle AU: no Punisher storyline. Characters and universe adapted for this story.)

​He has one rule: protect her 24/7 and keep his distance. ​Frank Castle is mature, cold, and disciplined to a fault-the family's most trusted bodyguard, an unshakeable presence. She is stubborn, defiant, and determined to test his every limit. ​By day, their relationship is strictly professional. But once the lights go out, forced proximity and heavy silences begin to chip away at Frank's iron restraint. ​Some lines should never be crossed. Especially after hours.

Her dad's best friend. Her childhood hero. The man next door. After eleven years, Frank Castle comes home. Charlie is twenty now. She's engaged. She's grown up. And Frank is about to learn that protecting her might be a lot harder than it used to be. Especially when he starts wanting more than he should.