BRUNSWICK — Maine’s Celtic duo Castlebay will perform joyous and mysterious seasonal songs and tunes from Ireland, Scotland and the British Isles on Friday, Dec. 18, at the SideDoor Coffeehouse.

Folk musicians Fred Gosbee and Julia Lane will blend the lilting sound of Irish flute, Celtic harp, fiddle and guitar with vibrant songs of revelry.

For 20-plus years, Gosbee and Lane have played and sung traditional music of Maine, as well as Celtic lands. In addition, they compose their own musical works. They weave history, legend, experience and humor into their music, which is filled with the symbolism of light conquering darkness and rebirth.

Castlebay’s performance will begin at 7:30 p.m. at the Unitarian Church, 15 Pleasant St. Tickets, $10, will be available at the door. For more information, call 373-1526 or e-mail [email protected].