"Lupin III: Goodbye Partner" is a 2019 anime special that centers on the exploits of the infamous thief Arsène Lupin III and his companions. The narrative begins with Lupin and his longtime partner, Daisuke Jigen, parting ways after a disagreement during a heist. Jigen, disillusioned with Lupin's reckless behavior, decides to retire from their partnership, leaving Lupin to continue his criminal endeavors alone.

The story takes a dramatic turn when Lupin encounters a mysterious woman named Nyx, who claims to possess a powerful artifact known as the "Alien Eye." This artifact is said to grant its wielder immense power, and Nyx seeks Lupin's help to unlock its secrets. Intrigued by the challenge and the potential rewards, Lupin agrees to assist her, unaware of the dangers that lie ahead.

As Lupin delves deeper into the mystery of the Alien Eye, he discovers that Nyx is being pursued by a shadowy organization intent on obtaining the artifact for their own nefarious purposes. The organization, led by a ruthless figure known only as "The Boss," employs advanced technology and a team of skilled operatives to track down Nyx and the Alien Eye.

Throughout the special, Lupin's resourcefulness and cunning are put to the test as he navigates a series of high-stakes encounters with The Boss's operatives. Along the way, he reunites with Jigen, who reluctantly agrees to assist Lupin in his mission. The dynamic between the two characters is a central focus, highlighting their deep bond and mutual respect despite their differences.

The narrative also features appearances by other familiar characters from the Lupin III universe, including the sharpshooter Goemon Ishikawa XIII and the enigmatic Fujiko Mine. Their involvement adds layers of complexity to the story, as alliances shift and new challenges arise.

The climax of the special sees Lupin and his allies confronting The Boss in a dramatic showdown, with the fate of the Alien Eye hanging in the balance. The resolution of the conflict underscores the themes of trust, loyalty, and the enduring partnership between Lupin and Jigen.

"Lupin III: Goodbye Partner" combines elements of action, suspense, and humor, staying true to the spirit of the Lupin III franchise. The special explores the dynamics of Lupin's relationships with his companions while delivering a self-contained story that appeals to both longtime fans and newcomers.