After a top secret chemical facility in the tropics is discovered manufacturing biological agents for use in weapons the higher ups of the project decide to quickly cut their losses and have the entire lab (and everyone in it) removed from the picture before it can be traced back to them. Enter Duke Togo, codename Golgo 13... the world class assassin hired to perform the job. After making some smooth progress in closing in on his target Duke soon finds out that he isn't the only one gunning for the secret lab and that a mysterious rival hitman has shown up to complicate matters. Can the two hope to work together to achieve a common goal, or at very least stay out of the other's way? Or is there something else entirely in store for the two legendary killers...?
- Against the Setting Sun: The climax of the story is set against the backdrop of the setting sun as two legendary hitman have a duel to the death on a remote island. Given that the title of the episode is "Deadly Shadow of the Setting Sun" this shouldn't be too surprising.
- Black Site: Golgo and AX-3's main target in this episode is a top secret chemical lab hidden on a small island out in the ocean.
- Crazy-Prepared: Both Duke and his rival AX-3. Naturally, Duke turns out to be the one who is more Crazy-Prepared in the end.
- Leave No Witnesses: This is the main reason Golgo and AX-3 were called in. After the island and its secret projects were uncovered and exposed the men running the operation decided it would be best to sweep the whole incident under the rug and prevent any of the scientists from testifying against them in court.
- One Bullet Left: Both hitmen are down to their last bullet when the job is finally done and they decide that only one of them is getting off the island alive. Ironically, AX-3 is one of Golgo's few opponents to not be killed with a Pretty Little Headshot and instead gets taken out by a thrown knife that Duke pulled off the corpse of a dead soldier.
