Naruto: Sasuke Retsuden - Uchiha no Matsuei to Tenkyuu no Hoshikuzu

Sasuke Uchiha heads for an astronomical observatory, far from the Land of Fire. There, he syncs up with Sakura, and together they dive into an undercover investigation in search of traces of the Sage of Six Paths! They discover a plan that goes beyond life and death, and a battle that will test this husband-and-wife team till death do they part.

(Source: VIZ Media)