Take heed: There are at least two acutely sad moments involving Robin Williams' Teddy Roosevelt in the latest Night at the Museum.

The movie, subtitled Secret of the Tomb, is imbued with the unshakable inevitability that even though we're still having fun, it's time to move on - a narrative made only more poignant by Williams' sudden and shocking death earlier this year.

It's hard not to concentrate on his every movement and word or to get antsy when he's in the midst of a bit and the camera cuts away to a monkey peeing on something, leaving us straining to hear Williams' voice. And yet, as silly a role and movie as this is, it also manages to live up to the (unfair) responsibility of being a comedy legend's last role. Director Shawn Levy and his team strike the right balance, without overwhelming the story with melancholy.