How should I finish my Children's Book?

I am writing and illustrating a children's book. It is a story about a little boy whose sister loses her favorite blankie, so he goes on an adventure to find it. The book starts with him looking out his window at night, and he thinks he sees a blankie floating down the road. He rubs his eyes, and then it's gone. The next morning his little sister is crying because her blankie is gone, and he tells his mom what he saw but she doesn't belive him. He decides to investigate the matter himself, so he walks outside and sees footprints, which he follows into the woods, and eventually to a very cool treehouse. I already have illustrations up to that point, and I would like to end the book with it being the dog who was actually walking under the blankie so it appeared to be floating, and the dog ends up curled up in the blankie. That doesn't necessarily have to be how it ends, and I am not exactly in love with the ending so I need help thinking of other ones I could use. THANKS