The chrysalis is a machine that can erase, transfer or manipulate memories. A burnt out police officer, David Hoffman, has his memory taken and wiped out by a renegade secret service agent. Hoffman is on a quest to find his memories and figure out why the people he's killed keep coming back to life. [Coventrey Telegraph.net and Chrysalis]

Bradbury himself has been involved in every step of the movie, which takes place in an Earth left barren after a third world war. Scientists in a research facility are struggling to find ways to revive plant life. One of the scientists apparently dies, but then a plant chrysalis grows around him and saves him. He starts changing into something new and scary. Here's a passage from the original story:

He could not see. But yes, yes, he could, and it was like the inside of a small dark red cavern, as if his eyes were turned inward upon his skull. And Smith tried to twist his tongue, and suddenly, trying to scream, he knew his tongue was gone, that the place where it used to be was vacant, an itching spot that wanted a tongue but couldn't have it just now.

His tongue was an itching spot.