"Tantei Opera Milky Holmes: Fun Fun Party Night - Ken to Janet no Okurimono" is a special episode within the "Tantei Opera Milky Holmes" franchise, focusing on the comedic and lighthearted adventures of the Milky Holmes detective team. The narrative centers around Ken and Janet, two characters who play a pivotal role in this installment. The story unfolds as the Milky Holmes team—comprising Sherlock Sherringford, Nero Yuzurizaki, Elly Cunningham, and Cordelia Glauca—prepares for a festive party night. However, their plans take an unexpected turn when Ken and Janet arrive with a mysterious gift, setting off a chain of events filled with humor, misunderstandings, and detective antics.

The gift, which initially appears harmless, becomes the catalyst for a series of comedic mishaps. As the Milky Holmes team investigates its contents, they encounter various challenges that test their detective skills and teamwork. The episode maintains a playful tone, with the characters' quirks and interactions driving much of the humor. Ken and Janet's involvement adds a layer of intrigue, as their intentions and the true nature of the gift remain ambiguous until the climax.

Throughout the episode, the narrative emphasizes the camaraderie and distinct personalities of the Milky Holmes team. Sherlock's over-the-top enthusiasm, Nero's aloofness, Elly's cheerful demeanor, and Cordelia's seriousness create a dynamic interplay that keeps the story engaging. The plot balances light-hearted moments with the detectives' attempts to solve the mystery, ensuring a blend of comedy and detective work that aligns with the franchise's signature style. The resolution ties together the various threads, providing a satisfying conclusion to the festive chaos while leaving room for the characters' continued adventures.