The plot as represented in the poster over there on your left, has to do with reincarnation, the discovery of anti-gravity, and immortality. Yes, it's pretty goofy. Chan plays a contemporary archaeologist named . . . Jack Chan. Not much of a stretch, I guess, especially since Jack Chan happens to have all the martial arts skills that you'd expect a guy with that name to have. He appears to be the reincarnation of a general from the Qin dynasty, and he dreams of having the general's adventures. His friend is interested in anti-gravity and believes the secret is, well, why go on? The plot doesn't matter. What matters is that Jack gets into a lot of fights, many of them sword fights this time, so instead of picking up things lying around to fight with, Jack just uses the sword. He's very good, in case you were wondering.
The best set piece in the movie takes place on a conveyor belt in a rat glue factory. There's some great comic action. Later on, in the anti-gravity underground tomb, there's lots of wire-work and CGI, something new in Jackie Chan movies, I suppose. In the section set in the past, the general has a terrific battle against hundreds of troops, another good set piece.
If you're a Jackie Chan fan, you'll probably get a kick out of this one, and of course you should sit through the credits. For more than one reason. Check it out.