Eternal Bond. Ghost Detective Short Stories, #11

Waking up in a sealed casket on its way to be buried would freak anyone out. Who wouldn't scream themselves hoarse - and try to claw their way out?Anyone who dies with unfinished business wakes up as a ghost. If this wasn't enough, the casket will only release them once they accept their new status, adding a whole new level of terror. But today's arrival stays quiet until the last mourner, a young woman at the front of the funeral procession, finally leaves...
That is when the screaming starts.