- "If we're in each others' hearts, Clark, I will always be with you. No matter what. I love you." - Lana Lang, Requiem
After seven months of being missing, Lana reappeared in Cuba where she was found by accident by Green Arrow while looking for Lex. Lana was surprised to learn that Oliver was indeed the Green Arrow and then proceeds to ask him how Clark was doing. Oliver suggested that she attend Chloe's wedding to find out for herself and after hesitating for a moment, she finally decided to return to Smallville. She attended Chloe's wedding reception, much to Clark's surprise. As Clark and Lana spoke about the decisions Lana had made about leaving, the Kryptonian beast Doomsday crashed the wedding and kidnapped Chloe.
Lana offered to help Clark find Chloe with the resources she had at the Isis Foundation. While there, she was visited by a woman who came from the future, and was informed that Chloe had been taken over by Brainiac. Lana was told that Chloe would have to be killed in order to stop him. After Clark rescued Chloe, Imra realized that Lana hadn't told Clark the reason she left after she woke up from her catatonic state, and what she planned on doing next with her life, but assured her that her secret was safe and that she would be remembered for more than just her relationship with Clark Kent. Lana was told by Imra that she has a destiny all her own.
Lana decided to stay in Smallville for some time and moved into Chloe's apartment while she was travelling to Star City.
During this time, Lana confronted Tess about a mysterious project and its relation to Lex's whereabouts and after stealing valuable information from her, Tess confronted Lana at the Isis Foundation and a physical fight broke out between the two. Lana won the fight and finally revealed to Tess that a nanochip had been planted into Tess' optic nerve and that she had been Lex's "eyes and ears" for a while.
The return of Lana also stirred past emotions between her and Clark. After Clark suggested their need for one another, they rekindled their relationship.
After Lana went missing and Clark began to suspect that she had been kidnapped by Lex, Clark learned about the real reasons why she left seven months ago and why she had come back. Actually Lana wanted to have powers for herself, so she was subjected to Lex´s Project Prometheus. Her skin was fused with a super suit made of nanotechnology and alien DNA, which gave her superpowers. After rescuing Dr. Groll from Tess, Lana ran away and finally called for Clark to meet her at the rooftop of the Daily Planet, where she explained her reasons as she wanted to devote her powers to working side by side with him. Clark finally accepted Lana's proposal and the two shared a kiss.
Finally being on equal terms, Lana and Clark began to enjoy their relationship and Lana announced her desire to join Clark in his patrol of Metropolis. However, their happiness did not last long as Lex devised a plan to separate Clark and Lana forever for having destroyed his life. As they investigate an explosion that occurred in LuthorCorp, Lana found that the bomb was enhanced with Kryptonite and was shocked to discover that her suit could absorb the energy of the Kryptonite.
After Lex informed them of his plan to blow up the Daily Planet with a Kryptonite bomb along with the rest of the city, Lex told the couple that they had to make a decision about what to do as Lana's suit could deactivate the bomb and absorb the Kryptonite, but this would also make her untouchable to Clark. After a moment's hesitation, Lana made the heartbreaking choice to sacrifice her love for Clark. She then deactivated the bomb, absorbing all the Kryptonite it held in it.
Unable to take off the suit, Lana finally decided to leave Smallville again. Knowing that this would be the last time he would see her, Clark moved close to Lana. Despite her objections, he kissed her one last time before weakening himself and falling to the floor in pain. Lana walked toward the staircase with tearful eyes, turned around and assured him that even though they couldn't be together, she would always be in his heart. They confessed their love for each other one last time, before Lana turned around and left the barn—and Clark—apparently forever.