where did the big bus go?

the little bus had fallen asleep very prematurely after a long day's journey. Something woke her up in the middle of the night. When this happens generally, she would toss and turn and usually be met with a warm big bus rumbling loudly and she would cuddle against him and immediately go back to sleep. So she tossed - and she turned. It was rather quiet too. she got up and looked around, but there was no warm fuzzy big bus! She was at home in her room. she felt hollow within, but covered herself and went back to sleep. poor little bus!