In a mysterious underground auction, a rare aquamarine gemstone called the Mermaid's Scale is put up for sale. The gem's owner forces Lupin to steal it, but he soon learns that the stone is a fake. The real Mermaid's Scale is hidden within an unsolved riddle, which holds the key to achieving immortality.
Lupin the III: Blood Seal ~Eternal Mermaid~
A highly prized aquamarine gemstone, the Mermaid's Scale, is put up for sale in a secretive auction. However, its owner forces Lupin to steal it, only to reveal that the gem is a fake. This deception sets Lupin on a journey to unravel a decades-old mystery.
