Let Us Be Gay tells the story of Kitty and Bob Brown. In a poignant prologue, the two separate as the girl pulls down her dream castle upon the discovery that her husband has opened its gates to the intruder. He protests, to her blank face, that things - despite all momentary affairs - are as they have always been and that to him, as to her, their love has been a perfect thing, untouched and untouchable. And, when she stares through him and his explanation, he goes away. They meet again, after three years, under delightful, if somewhat farcical, circumstances. In answer to the plea of as crustily wise an old lady as ever was, Kitty, a different Kitty, drops into a Westchester house to rescue a wandering granddaughter from a mistaken love. And she discovers, blinking in surprise, that the man she is to captivate to effect this rescue is her first husband. In the last act she goes back to him. But as Miss Crothers writes it, it is not so obvious. Nor is it so obvious that, after having advanced all the excellent reasons to the contrary, she should turn to him as the last act curtain starts down and beg: "Take me back again."