After Clark Kent destroyed Brainiac, Lana recovered from her coma, but when Clark came to visit her, she wasn't there. He was given a video she had made for him, telling him that she was standing in the way of his destiny, and that she would always love him but that the world needed him more then she did. However, this was not the true story: Lex Luthor had gotten his people (including Tess Mercer) to kidnap Lana and have her brought to him. They forced Lana make the goodbye-video to Clark, with her proclamation of being a distraction to his destiny and not to look for her so that Clark wouldn't know what was going on. She was chloroformed unconscious and put into a van. However, Lana managed to hijack the van and escape.
When Lana returned for Chloe Sullivan and Jimmy Olsen's wedding besides wanting to be there for her friends, she also had some plans of her own involving Tess. Lana confronted Tess in the Luthor Mansion, saying that she knew that Tess has been spending most of Lex's money on a project called Prometheus and that Lex was alive. Lana also told Tess that Lex wasn't the man she thinks he is. Tess said that Lana doesn't know Lex like she did, to which Lana replied: "For your sake, I hope you're right." Lana left, revealing that she stole something from Tess.
Lana was at the Isis Foundation talking to someone, telling them she stole the information from Tess's drive. She was using a wireless head set and it was unknown who she was talking to. She gave the person the information and was about to leave when Tess arrived. Tess told her that maybe her judge of character wasn't as good as she thought it was but she now saw what Lex saw in her, that she was both sneaky and stunning. Lana replied what Lex what saw in her was an equal. The two begin to argue. Lana moved to walk out the door when Tess pulled a gun on her. Lana managed to knock the gun out of Tess' hands and a fight ensued with Lana eventually getting the upper hand when she picked up the gun again and pointed it at Tess. Still holding Tess at gunpoint, Lana brought her into her surveillance room and asked Tess if she was this devoted before or after her accident, slightly impressing Tess with this knowledge as Lana stated the details of this "accident". Tess told Lana that Lex saved her life so she owed him everything. Lana revealed to Tess how Luthors repay that kind of loyalty; she showed her a live feed on the screens of everything Tess was seeing, explaining that Lex implanted nano-transmitters in her optic nerve so she could be his eyes and ears. Tess was horrified as everything she saw was shown and everything she heard echoed. Lana apologized to Tess, saying that Lex may have saved her, but he never trusted her.
Clark arrived to the Talon looking for Lana to find the apartment ransacked and Tess there instead. Clark found out that Lana was missing and at first blamed Tess, but Tess told Clark that it wasn't her and she came to warn Lana, who has been investigating some dangerous LuthorCorp technology. Clark asked her since when have Lana and Tess become friends, Tess replied that since Lana showed her the real man Lex was. Tess told Clark the real story of why Lana left Smallville after she came out of her coma. Clark yelled at Tess for it and pushed her against the wall. Tess told Clark she was sorry and that Lex said it was for Lana's own good and that she was in that coma because of Clark. Tess told Clark she thought Lex may have kidnapped Lana again, however this was untrue as Lana wanted to use the Prometheus technology on herself. Tess arrived at the lab and demands the Prometheus suit. Dr. Edward Groll warns her by opening the chamber she may kill Lana. Tess wanted Prometheus to be destroyed and prepared to shoot Lana. Tess fires a shot at the control panel and a second at Groll. Clark arrived and saw Lana burst out of the chamber, stop the bullet, knock out Tess and run away with her super speed. Later at the mansion, Tess called her people to find Lana, and entered the library to find Lana burning the Prometheus folders. Tess began to run but Lana cut her off. She told Tess that she was there to be her friend and she had been down this path that she knew Tess wanted revenge on Lex, but not to be a victim and forget about Lex. Lana told Tess that she was an amazing woman and not to let Lex take that away from her.
In all the other Superman movies, comics and such, Lana Lang is a redhead. Though not in Smallville, where she is a brunette and Tess is the redhead.
Given that Lana was married to Lex during the end of Season Six and that Tess revealed to be Lex's half-sister in Season Ten's Abandoned, at some point and time, Lana and Tess would have been sister-in-laws.