The lethal drug Mash sweeps across Japan leaving a trail of bizarre crimes that only The Iron Cross Army can be behind. As narcotics officer Go Tachibana is brought in to investigate Takuya decides to do a little detective work of his own. After a wild-west shot-out puts Tachibana's young son in danger the inspector's dark past is revealed. Teaming up with Spider-man to end the threat of Mash once and for all, Detective Tachibana and Spidey face-off against, the mushroom crazed Kinokogar in a battle for the ages.