A dying mob boss entrusts Lupin with a diamond that supposedly is the key to a vast treasure. But when Lupin is attacked by an assassin and saves a mysterious girl from trouble, it becomes clear that that there's more to this treasure then meets the eye... (Source: ANN)
Anix is the best site to watch Lupin III: Twilight Gemini no Himitsu
SUB online, or you can even watch Lupin III: Twilight Gemini no Himitsu
DUB in HD quality. You can also find
anime on Anix website.