Nathan entered the cellar. Mason entered the cellar. The watermelon is in the green bathtub. Mason exited the cellar. Nathan moved the watermelon to the green suitcase. Mason entered the cellar.
Mason think that Nathan searches for the watermelon in the green suitcase.
 Mason think that Nathan searches for the watermelon in the green_bathtub
 Mason think that Nathan searches for the watermelon in the green_suitcase