Catriona "Cat" Rogers, played by Maleeka Gasbarri, made her first screen appearance on 19 January 2015. The character's picture was previously seen in the episode broadcast on 28 November 2014, while Gasbarri's casting was announced on 15 January 2015. Gasbarri was cast in the month-long guest role after she was spotted by a Neighbours casting agent at an Australian Film and Television Academy course in Perth. Gasbarri filmed an audition tape in her home town of Dunsborough and sent it into them. She continued, "They said I had gotten the role and had to be there in two weeks to start filming. It was a bit overwhelming, but I was so excited."
Cat is Erin Rogers's (Adrienne Pickering) daughter. She was taken into care when her mother became addicted to drugs. Erin tells Sonya Mitchell (Eve Morey) that Cat does not want to see her, and they only communicate through Facebook. Sonya's husband, Toadfish Rebecchi (Ryan Moloney), sets up a meeting between Cat and Erin, but Cat pulls out at the last minute as she is too nervous. Cat asks for another meeting and turns up early. She bonds with Toadie over BMX bikes and talks with her mother. Cat leaves abruptly when she learns that Erin came to see her cricket matches, but did not speak with her. Erin writers Cat a letter and she returns to see Erin. They bond while playing cricket and when Erin asks Cat to stay a few days, she agrees. However, when Cat turns up she learns Erin has gone. Toadie and Sonya allow Cat to spend the night with them. Cat later asks Sonya and Toadie if she can live with them, as she does not want to stay with her foster parents, who she feels do not want her as they are expecting a baby. Sonya invites Cat's foster mother, Lorraine (Michelle Celebicanin), over to talk. Lorraine convinces Cat that she is wanted and Cat decides to return home. Before she goes, Sonya and Toadie tell her she can visit anytime.
Michelle Kim, played by Ra Chapman, made her first screen appearance on 6 February 2015. Chapman finished filming with Neighbours during the week beginning 18 April 2015. Michelle is an associate of "dodgy" businessman Dennis Dimato (David Serafin). Chapman compared Michelle to her role as Kim in prison drama Wentworth, saying she was more toned down, but just as "tough". She continued, "In Wentworth, my character takes the lead while in Neighbours, she is running an illegal car racket and is relentless in getting what she wants. Sometimes a bit scary." Chapman enjoyed playing Michelle, as she evolved to become "tougher and meaner".
When Matt Turner (Josef Brown) starts a new job as a security guard at Dimato Industries, he meets with Michelle, who tells him his duties. Michelle tries to befriend Matt and offers him a dress from surplus stock for his wife. She later calls her boss, Dennis Dimato, to tell him that getting Matt onside will not be hard. Matt quits his job after learning he is working for Dimato, but soon meets with Michelle to ask for it back as he needs the money. He later asks her for extra shifts. Michelle meets Tyler Brennan (Travis Burns) and gives him the details about his new job stripping stolen cars for parts. Michelle later congratulates Tyler for stealing items on a list given to him by Dimato, and she asks him to continue working for them. She exploits his strained relationship with his brother Mark (Scott McGregor) and convinces him to steal cars. When Tyler takes a car that is tracked by the police, Dimato is arrested. When he gets out on bail, he and Michelle buy Fitzgerald Motors to use as a cover for their business. Dimato flees the country and leaves Michelle in charge.
When Bailey Turner (Calen Mackenzie) takes one of the stolen cars, Michelle demands that Tyler steals a replacement or give her $8,000. After learning Paige Smith (Olympia Valance) reported the stolen car to the police, Michelle blackmails her into helping Tyler. He tries to persuade her to leave Paige out of it, but Michelle makes her the new garage assistant. A few days later, Michelle tells Paige that they have drop off some car parts. However, the police, having been tipped off, arrive and Michelle and Paige try to escape. Michelle trips and sprains her ankle, but Paige helps her. At the hospital, Michelle claims she tripped running for the bus. She accepts Paige's plan to run the garage as a legit business. Dimato later returns to town and reunites with Michelle and their group. Tyler tries to run and Michelle suspects he is spying for the police. When the police eventually arrive, Michelle tries to escape, but Paige trips her up with a dustbin and she is arrested.