There once was a boy named Milo who didn't know what to do with himself--not just sometimes, but always. And then the dragons arrived. The Phantom Tollbooth - Norton Juster

When Mary Lennox was sent to Misselthwaite Manor to live with her uncle everybody said she was the most disagreeable-looking child ever seen. And then the dragons arrived. The Secret Garden - Frances Hodgson Burnett

The glorious city of God is my theme in this work, which you, my dearest son Marcellinus, suggested, and which is due to you by my promise. But now the dragons have arrived.