If you guessed that the title 'Crimson' indicates that Clark will again come into contact with Red Kryptonite, congratulations: you're a master of discerning the obvious. This time the Red Kryptonite comes in the form of an aphrodisiac lipstick worn by Lois Lane. Once she lands a smooch on Clark his 'other' self comes out, and this time it is time to confront the ladies of his life, with doe eyed Lois in tow.
After romping around lustfully with Lois for a while (resulting in a temp tattoo on Lois), Clark decides to crash Lex and Lana's engagement party, and it is not a pretty scene. Not only does he chastise Lana and Lex at the party, but also his own mother. Insinuating Ma Kent herself is simply there to marry into the Luthor name. Ultimately he reveals to everyone that Lana is pregnant and that is the only reason she is marrying Lex. While he is at it he also admits to Chloe that he has considered firing up a relationship with her in the past. A move sure to complicate things between her and Jimmie who has shown up with an antidote to the Red Kryptonite. Clark kidnaps Lana and takes her back to his loft where he tries to get her to admit that she is still in love with him. While she refuses to speak the words, she does allow a pretty deep kiss - something for Clark to hold over Lex's head when he shows up a few moments later wielding a gun. The two struggle and in the process an iron bar is mangled in an attempt to cold cock Clark. Lana sees this and keeps the piece as a memento. Ma Kent shows up with a little green kryptonite to save the day. After the red kryptonite hangover, ma Kent tells Clark that the red exposed issues he needs to start dealing with. Back at Lex's place, the doc checks out Lana and says that everything is okay; considering the 'specialness' of the pregnancy. Lana, meanwhile, secretly examines the iron rod... beginning to wonder.