She usually 'stumbles out of bed' [=gets out of bed] around 7:00 am.
I 'stumbled across/on/upon' [='found'] this book by chance.
They 'stumbled on/upon' [='discovered'] a bizarre plot.
(..) "forsake all claim to your inheritance and start north. "If you do not," he said, "then we'll have a hunt "and somewhere in these woods your horse will stumble "and you'll be thrown from your saddle to die. "Or so I'll tell your mother. "Nothing would please me more." Ser Alliser's going to make me (..)2011 TvShow: Game of Thrones Title: Cripples, Bastards, and Broken Things Season: 1 Episode 4