Timeslip

What is Timeslip about (plot, summary)
Three children have vanished from the tiny Midlands village of St Oswald. First to disappear is local girl Sarah, then Simon Randall and Liz Skinner, who are on holiday with Liz's parents. Only Commander Traynor, an apparent stranger to the area, can offer some idea of where they are and that idea is so incredible and horrifying that the Skinners cannot believe it...