With their necks stretched high , Mr. and Mrs. Quack watched . They were ready to take to their strong wings the instant they discovered danger . But they did not want to fly until they were sure that it WAS danger approaching . They were startled , very much startled . Presently they made out what looked like the branch of a tree moving over the water towards them . That was queer , very queer . Mr. Quack said so . Mrs. Quack said so . Both were growing more and more suspicious . They could n't understand it at all , and it is always best to be suspicious of things you can not understand . Mr. and Mrs. Quack half lifted their wings to fly . CHAPTER XXX : The Mystery Is Solved It was very mysterious . Yes , Sir , it was very mysterious . Mr. Quack thought so . Mrs. Quack thought so . There , out in the Big River , in the midst of the Black Shadows , was something which looked like the branch of a tree . But instead of moving down the river , as the branch of a tree would if it were floating , this was coming straight across the river as if it were swimming . But how could the branch of a tree swim ? That was too much for Mr. Quack . It was too much for Mrs. Quack .
So they sat perfectly still among the brown stalks of the wild rice along the edge of the Big XXXXX , and not for a second did they take their eyes from that strange thing moving towards them .
Mrs. Mystery Quack River Sir XXX danger instant things tree