Kenritsu Chikyuu Boueigun

Prefectural Earth Defense Force

The nefarious Phone Pole Team has one goal - world conquest. However, this has proven difficult, so they're revising their strategy and taking over the world one prefecture at a time. When the mayor's office of their current target learns of their plans, they recruit every member of the high school baseball team (all three of 'em) to combat this threat. Over the course of this one-shot OVA our heroes must contend with Faceless Minions(tm), rampaging cyborgs, desperate attempts at undercover work, and perhaps even a touch of romance, all in their efforts to protect their neighborhood... and justify the stipend given to them by the city council.

(Source: Anime News Network)