Mrs. Fat is slowly succumbing to cancer, but her biggest worry is her only child, the 30-year-old Bee. Possessing the mind of a toddler but the hormonal urges of a sexually aroused rhino, Bee finds himself in trouble with the gangster boyfriend of his neighbor May. After the thug is killed for stealing some heroin, the pregnant May becomes severely disabled -- and after Bee's real mother dies, the surrogate mother for her new friend.

发嫂（叶德娴 饰）独自抚养着儿子阿B（谭耀文 饰），因为先天的缺陷，这个三十多岁的男人只有着十五岁少年的智商和认识。随着时间的流逝，发嫂年岁渐长，繁重的家务和沉重的压力让她渐渐有些力不从心，祸不单行的是，一次偶然中，发嫂发现自己竟然患上了无法治愈的癌症。

自己的去留并不重要，重要的是该将懵懵懂懂的阿B托付给谁，这成为了发嫂最大的难题，就在这时，一个名叫阿May（关秀媚 饰）的年轻女子出现在了阿B的身边。然而，发嫂很快便发现，阿May对于阿B的利用大于关心，这令她十分但又，幸运的是，阿B的忠心不二和善良纯真最终感动了阿May。