AbbaFab, the hugely popular Abba tribute band, are in trouble. Gemma Redden, aka Agnetha, has just broken her ankle and finding a new singer to fill her white platform boots at such late notice isnt going to be easy. Desperate times call for desperate measures and the youngest Redden sister, Mia, reluctantly agrees to don the blonde wig and sky-blue hot pants. For Mia, a shy piano teacher who has felt third best all her life, this is her big chance to prove herself to her two big sisters, Wendy and Gemma. Meanwhile, Mias oldest friend, Alva Ryan, is having a life crisis of her own. Her previously devoted boyfriend, Sean, has just walked out, and this time hes not coming back. Things come to a head when Wendy has a terrible accident. Because Wendy has been keeping a secret; a secret that could blow the band apart and devastate the close-knit Redden sisters. But secrets have a way of coming out when you least expect them to. And sometimes even the best of sisters gets it horribly wrong.