Mao is split up from Meirii and Siro in a forest at night. When they regroup they find a large house where they are served a very nice meal by the chef there. The sickly owners however only want to have red congee. Mao and gang try to find the secrets of this addictive congee and find it is made from a poisonous red mushroom. Also they find out the chef wanted to use this addictive red congee to force the owner's to sign a contract to give all their money and their daughter to him. And so Mao creates a herbal 'five colour' congee which he gives to the owners. This cures their addictiveness for red congee and the chef is forced to leave.
小当家、四郎、嘟嘟在森林里走失了，结果竟不约而同闯进一间好像鬼屋的房子里。里头的男女主人脸色难看的简直像幽灵一样，连女儿小兰也虚弱不堪。原来是一名企图谋取翡翠馆财产的坏厨师在用掺了毒的红粥控制了这一家人。所幸小当家识破他的诡计，用他特制的"彩虹粥"解救他们。
山奥で迷ってしまったマオたち三人は、古城という風情の大邸宅に泊めてもらう。だが、その家の住人も召使いも、幽霊のような顔つきをしている。夕食で一家は真っ赤なお粥が出されると目つきが変わり貪り食い始めた。
