Herbert is excited to see his visiting brother Timothy Gillis, until he learns of Timothy's visit. Timothy, an oil baron, is off on another job, meaning he wants to leave his sixteen year old son, Duncan Gillis, with him for an extended stay. It's not that he doesn't like Duncan, but he just can't stand having a teenager in the house again, now that Dobie is grown up and more mature. Dunky, as they fondly refer to him, is indeed a younger version of Dobie, with only girls on his mind. As such, Dobie takes Dunky under his wings to help him win the affections of Clarissa Spangler. To do so, Dobie suggests Dunky manufacture some family tragedy to appeal to Clarissa's sympathetic side. It works, but Dobie may not appreciate it when he learns what the tragedy is: that he's a drunk. But if that tragedy worked for Dunky, it may even work better for currently girlfriendless Dobie, who may need someone pretty to rehabilitate him.
—Huggo