Mission Cantina is that rare Western Massachusetts restaurant that ventures into Boston territory - others include Osaka and Bueno y Sano - and the Mexican restaurant has shared a sneak peek of what will become the bar of its imminent Brookline expansion. The above photo was posted to Facebook earlier today along with another that declares "Back bar mission Boston !!" The new location is headed for the former Beacon Street Tavern space. Stay tuned for updates and drop any of your own to the tipline.