This Smallville spoiler is for season 8, episode 16 which is titled Turbulence.
A lot of things go on in this episode, especially right after the season 8 episode 15, Infamous in which we discover that Davis can control the evil within him.
Now the thing that changed from when Clark went back into the past was the fact that Davis can control Doomsday coming out. It was said that Chloe will be torn between him and Jimmy now that she has no idea that he is doomsday.
It is said that Jimmy gets violently angry seeing Davis back in town after what happened in the past with the wedding and Davis kissing Chloe.
On the other end, Tess (played by Cassidy Freeman) knows a little about Clark’s power so she decides to set a trap for him to expose his powers. Tess invites Clark to a press conference in New York and when they take the private jet, an explosion forces the plane to go down. Now Clark is forced to save her.
Tess also mentions that Lex used to talk about Clark a lot hinting that she knows about his true identity and powers.
That’s it for now, check out the Turbulence trailer: