Birdy trades the spy thriller setup for pure comedy chaos, and it works because the show trusts you to care about Tsutomu's hopeless crush enough to wreck everything for a laugh. A Federation marionette crashing a love confession is the kind of absurd escalation that only lands if you've watched the actual seasons, this OVA has zero interest in being a standalone entry. The energy shifts from "alien cop in a human's body" to "let's see how badly this can go," which is exactly where the character dynamics have been heading anyway.

Birdy finds herself playing matchmaker when Tsutomu needs help winning over Sayaka, enlisting her pin-up persona to orchestrate the perfect romantic setup. A fresh assignment sends Birdy, in her Shion Arita identity, to Kobe, the city where Sayaka Nakasugi now lives. Tsutomu Senkawa is anxious about Sayaka, so Birdy heads over to see her, but the pair turn out not to be the only ones with an interest in her. When a Federation marionette enters the picture, the romantic scheme goes badly off the rails. Mixing action, comedy and science fiction, this single OVA links the first and second DECODE seasons.