Page 68 of Physik (Septimus Heap 3)

And this was how, at long last, Lucy Gringe found her way to Simon Heap. For Stanley, ex-Message Rat and member of the Secret Rat Service, knew where Simon was—although it took many talks at cross-purposes and many long hours of listening to Stanley's reminiscences before Lucy discovered exactly what Stanley knew. The Big Freeze had already set in when Stanley at last agreed to take Lucy to the Badlands, and it was not until the spring of the following year that they actually set off. By late spring, Lucy and Simon were reunited at last.