The fourth movie under the LUPIN THE IIIRD series of films.

A special invitation has been sent to Lupin and his crew to an uncharted island. The invitee is believed to be the mastermind who controls the world's top mercenaries and is connected to crimes throughout the world! Who could this mysterious person be? The answer lies on the uncharted island hidden away from existence. To find out the identity of the mastermind and steal his vast wealth, Lupin and his crew as well as Inspector Zenigata, in his attempt to capture them, are led to this mysterious island. The island is shrouded full of mysteries including old discarded tanks and firearms along with strange and mysterious inhabitants. Supposedly the dead assassins from his past are there waiting for Lupin and his friends.

(Source: POM Anime)