Leanna Cavanagh is the troublesome daughter of local GP Liam Cavanagh. Leanna's mum died and Liam married Maya Stepney, who Leanna developed a hatred for. In March 2018, she partnered with Jacob Gallagher for a science project, and on their fourth study date, he introduced her to his step-father David Metcalfe and David's wife Tracy. A few days later, Leanna, Liam and Maya went to dinner with Jacob, David and Tracy which ended in disaster.
Leanna, Jacob and Gabby Thomas missed the bus for school, so the trio stole Ross Barton's car to get Gabby to her exam on time. The car ended up running out of petrol so the teens ditched the car. A few weeks later, Leanna and Jacob decided to cause trouble with Joe Tate by smashing up his car, instead deciding to take it for a joyride with Noah Dingle and Sarah Sugden.