Its Sereias 18th birthday and she does something that she hasnt done for five years – she falls out of bed waking her up ten minutes before her alarm is due to go off.Her duvet is wrapped around her when she falls and she assumes that this is why she cant move her legs. But when she disentangles herself from the duvet she is in for a shock – her legs have disappeared and in their place she has grown a fish tail overnight.Shes supposed to be meeting her friends for a night out – hows she going to explain that shes turned into a mermaid overnight?