Now you see her, now you don't - Diana G Gallagher

What's going on? For no apparent reason, Sabrina keeps popping out of real life and into a novel or TV programme! Then a few seconds later she pops back into the real world again. So far no one has noticed her strange disappearances, but for how much longer?
Sabrina can't work out what is happening to her and there is a party at the skating rink tonight. What if she is skating and suddenly disappears? Even worse, every time Sabrina pops out, she's gone a little longer. If this keeps up, she could disappear from real life completely.