Werewolf Monster's Huge Murder Party

Werewolf Monster's Huge Murder Party (怪人狼男の殺人大パーティー Kaijin Ōkami Otoko no Satsujin Dai Pātī) is the thiirty-ninth episode of the original Kamen Rider Series and the franchise's first Christmas episode, which aired on Christmas Day in 1971.

Plot
On a moonlit night, two drunk office workers are stumbling home from an office party with one of them named Urabe stopping and going off to find a bathroom. After waiting a minute or two, his co-worker has to go too and then stumbles over Urabe who is lying unconscious. The man goes to check on him, only for Urabe to start turning into a werewolf. The co-worker tries to flee from the werewolf but he catches him and bites his neck, killing him. The werewolf is then surrounded by Shocker Combatmen and Colonel Zol arrives, ordering the Combatmen to capture their "valuable test subject". The Combatmen struggle to capture the werewolf as it fends them off, but Colonel Zol uses a blowgun to tranquilize the werewolf and the Combatmen capture him. The leading Combatmen says that the results of the "Wolf Virus" are impressive, but Colonel Zol berates his subordinate for letting his test subject escape and run around the city, thus potentially tipping off their enemy Kamen Rider to their activity. He orders his men to dispose of the corpse and all traces of evidence that could be left behind. As Colonel Zol oversees this, he hears a noise and then finds a child's shoe and a girl's doll. He thinks that the doll belonged to the dead man's child as a Christmas present, but as he walks away, a little girl is seen hiding from him, upset that Zol took her doll and slowly sneaks away from them.

At the Midori Kusa Orphanage, Kazuya Taki, Michi, Tobei Tachibana and Hayato Ichimonji are helping decorate the Christmas tree for the kids. Kazyua asks a boy what he wants for Christmas as if he's been good, Santa will bring it. The boy responds by saying he wants to meet Kamen Rider more than seeing Santa with the girl next to him agreeing. Hayato (who is secretly Kamen Rider), is seen with a reluctant look on his face, but his friend Kazuya promises that Hayato will bring Kamen Rider here with Hayato finally agreeing. As they finish the tree, the excited kids tell Ms. Sanne that Kamen Rider is coming to visit them for Christmas instead of Santa. Ms. Sanne is concerned asking Hayato and Kazuya if it is okay making such a promise. Hayato says he would never do anything to shatter the dreams of children. Kazuya wonders where Kumi is and Ms. Sanne says that she came down sick with a fever last night. Hayato goes into her room to check on her