`Abbafab`, the hugely popular Abba tribute band, are in trouble. Gemma Redden has just broken her ankle and finding a new singer to fill her white platform boots at such late notice isn`t going to be easy. But 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 older sisters, Gemma and Wendy. Meanwhile, Mia`s oldest friend, Alva Ryan, is having a life crisis of her own, Her builder boyfriend and all-round-good-guy, Sean Malone, has just walked out and this time he swears he`s not coming back. And Alva`s sister, Kerry, is having rather unusual problems of her own. Things come to a head when Wendy has a terrible accident. Because Wendy is harbouring a secret that could blow the band apart and devastate the close bond of the 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.