The Bearcats were paced by Denver Lynds, who scored once and added three assists, and G Blackmore who potted a pair of goals, including the winner.
As was the case in the best-of-seven series opener, the game was a seesaw battle as the teams were deadlocked at two after the opening frame and Miramichi led 3-2 after 40 minutes.
Brandon Hughes and Nic Blanchard had the other Truro goals, while netminder Jason Rioux stopped 29 of the 33 shots he faced. The Bearcats had 29 shots on the Miramichi net.
Josh Shatford led the Timberwolves with a goal and two assists, while Campbell Pickard and Makail Parker had the other markers.
Next action in the best-of-seven is Thursday in Miramichi at 7:30 p.m. Game 4 is back in Truro Saturday at 7 p.m.
