When Spartacus the old family dog starts looking poorly, the Brown children reluctantly decide the time has come to put her in a home. But when the Brown children decide how to break the sad news to their mother, Agnes gets the wrong end of the stick. Under the impression that her children are planning on putting her in a nursing home, a furious Agnes sets out to persuade her children she's not going senile. Meanwhile, Cathy's new boyfriend Professor Clowne is determined to interview Agnes for his new book about motherhood and won't take no for an answer. Agnes reluctantly agrees to the interview but then becomes convinced that Clowne actually wants to study her to prove that she's going senile. Moreover, with Agnes's birthday fast-approaching, the Brown family have decided to throw their mother a surprise party. But poor Agnes is expecting a completely different surprise...