The show follows the lives of the teachers and the pupils at the eponymous school of Waterloo Road, a failing inner-city comprehensive, tackling a wide range of issues often seen as taboo such as the difficulties faced by split families, cybercrime, adultery, illiteracy, domestic violence, nervous breakdown, anger management issues, drug overdose, test anxiety, assault, poverty, starvation, photo manipulation, video game addiction, cyberbullying, anorexia nervosa and borderline personality disorder.

Leo feels neglected so he is happy to be befriended by new girl Mandy, only to be taken aback when she displays a sudden burst of violent behaviour toward Justin.

Justin is struggling to deal with the breakdown of his relationship with Tiffany and erupts in a fit of uncontrollable rage, which comes to a head when he punches Allie.

Hector pushes Sue to be with him but is left in the cold when she makes it clear she needs some space, while Darren arranges a surprise for Grace but she's not too happy about it.

It's a new term, and Vaughan is ready to battle to stop the proposed merger, resulting in the employment of Lorna Hutchinson, and opening the school to troubled pupils, such as Scott Fairchild and Kenzie Calhoun.

Note: First appearance of Lorna Hutchinson, Carrie Norton, Kenzie Calhoun, Bonnie Kincaid, Scott Fairchild and Dale Jackson.

Dale's erratic behaviour leaves Maggie and Lenny concerned, but he shuns their support and continues to seek his next big adrenaline rush.

Abdul is nervous about meeting his birth mother, while Bonnie is devastated by the result of the police investigation into her cyberbullying case, and Vaughan finds out about a surprise inspection in advance.

The decision day arrives, but with no Vaughan to lead them, the pupils are forced to take matters into their own hands — and soon discover the council is not being entirely honest about its plans.

The final line of the series is a quote from Grantly Budgen, the show's longest-serving character: "...I turned up for a week's cover - ended up staying 25 years".