The Prison Beneath the City

An urban explorer discovers secret tunnels beneath a modern city leading to an underground prison abandoned after a mysterious riot decades earlier. Strange messages cover the walls warning visitors not to go deeper after midnight. The explorer and friends uncover horrifying experiments conducted on prisoners involving sleep deprivation and mind control. Something in the darkness still stalks the tunnels, hunting anyone who enters. Include suspenseful underground exploration, terrifying creature encounters, emotional panic, and revelations about government cover-ups.