Detective Conan: Love Story at Police Headquarters - Wedding Eve Meitantei Conan: Honchou no Keiji Koi Monogatari - Kekkon Zenya

The special contains the footage from episodes featuring Takagi and Sato, with a new narration from Conan and re-recorded line of Takagi and Sato.

In the end scene, Sato is preparing herself as the bride as Yumi approach her. Meanwhile, Takagi is waiting outside. Those scenes are leading to the events in The Bride of Halloween.

(Source: DCW Wiki)