Sita Desai is the cousin of Chesney Karib, she moved onto the Chatsworth Estate in Series 8 under their grandfather's orders to keep an eye on Chesney and how he runs the Karib's Shop. She is a first year Medical Student with ambitions of becoming a Doctor. She revealed to Carl Gallagher that her father went to Pakistan to arrange a business deal when she was 9, he ran off with his cousin and left her mother with four children under 9 to raise alone, she said that this was a secret and everyone else thinks he died in a car crash.
Early in Series 8 she failed her Medical School exams, and was distraught at what she saw as the possible end of her dreams. After consulting her tutor she received an ultimatum, if she slept with him she'd pass all subjects. She revealed how upset she was when drinking a straight Vodka at The Jockey, something very out of character for the Muslim who had refused to drink alcohol up until that point. She managed to defuse the situation and pass her exams when Carl Gallagher who was completely smitten with her came to her rescue. She told her tutor that she accepted his advances and took him to the Jockey toilets to have sex, while Carl hid in the cubicle next to them and filmed the action with his phone. Before anything actually happened they revealed to the tutor what they were doing and he agreed to back off and pass her, in fear of losing his job, leaving Carl to kick him in the crotch at walk off.
Carl Gallagher then spent most of his time pursuing the apparently confused Sita, who clearly had feelings for him but seemed unable to decide whether to act on them. Their flirting eventually came to something when Carl roped Sita into driving a car for him on a Maguire job because he couldn't drive with an injured hand. When the day came Carl had forgotten where the car had to be taken, so they followed the directions marked "Home" on the car's Satellite Navigation System only to find out that the car was stolen and they had just driven it to the real owner's home! While the owner went inside to get some ID, they quickly sped away only to be chased by Police, beginning to panic Carl admitted that his hand was fine and he'd just used it as an excuse to bring Sita along. Thinking on his toes Carl concocted a plan and he had Sita slam on the brakes then run into a nearby Shopping Mall with him, inside they ran up the stairs and threw off their jackets to help hinder recognition before hiding in an empty room. They successfully escaped the Police and in their adrenaline fueled relief had sex right there on the floor.
After this they continued to have regular sex, whenever they were left alone in the shop until one time, right in the middle, Carl asked Sita to marry him. Shocked at the proposal Sita ran off to the shop front where her Auntie Usma's presence made it impossible for Carl to speak to her. Sita later told Carl that there was no relationship, that her family would never allow them to be together because he wasn't a Muslim. Though Carl promised to convert for her she told him that she was moving to Pakistan for an arranged marriage soon. Sita later admitted to Chesney that she had lied and there was no arranged marriage, she had just said so to quiet Carl. Ignoring his promises, Sita departed the Chatsworth Estate for Pakistan, while she had said she would return and just tell Carl she was married to keep him off her back, Chesney had angrily told her that if she left she was to never come back.