This season continues with the misadventures of Dobie Gillis and his best friend Maynard G. Krebs at Central City's S. Peter Pryor Junior College, Dobie continuing to deal with life with his parents, Herbert and Winifred Gillis, and working in (or trying not to work in) his father's grocery store.
Sheila James and William Schallert left Dobie Gillis before the start of the fourth season; Schallert to star in the pilot for Philbert and James to star in the pilot for a Dobie Gillis spinoff, Zelda.
Both shows went unsold, and James returned to Dobie on a freelance basis for four episodes towards the end of this final season.
Dobie and Maynard are working as janitors in a high rise office building.
They hear the siren of a fire truck and see a large crowd down on the street.
Dean Magruder (Raymond Bailey) is holding a hearing as to whether or not Maynard should be kicked out of school.
Dr. Litweiler (James Millhollin) describes the tests they performed on Maynard and how things didn't go well.
Thalia Menninger (final appearance of Tuesday Weld) wants a list of Dobie's assets and net worth before she'll let him propose to her.
Dobie tells her that he made her the beneficiary of his GI insurance policy worth $10,000.
Dobie is late for a class and Thalia tells him a short cut, which turns out to be a firing range.
Things start happening to Dobie and he believes Thalia and Maynard are plotting to murder him.
Dobie then hears what sounds like Herbert and Winnie planning on helping Thalia.
Tim travels a lot digging oil wells, so he doesn't get to visit often.
"Dunky" comes in the store with Clarissa Spangler (Ahna Capri), a girl he just met outside.
Dobie suggests that he find some family tragedy to appeal to Clarissa's sympathy.
Donna mistakenly believes that Herbert and Winnie are encouraging Dobie's drinking.
Dobie confesses to Maynard that he doesn't love Zelda, but she can help him through life.
Clarissa Osborne tells Chatsworth that their entire fortune of $30 million has been wiped out.
Chatsworth pressures Maynard and Dunky into raising money for a needy family in town.
To pay Herbert, Clarissa says she'll take a job as the Gillis' maid and Chatsworth will be the butler.
Mr. Nichols (Richard Clair), a tax assessor, comes by and Herbert tries to make things look poor.
When Nichols sees all the fancy items and a maid and butler, he raises Herbert's taxes.
Dobie tells us how Maynard and Zelda came to be standing in front of the Justice of the Peace (Burt Mustin) getting married.
Zelda finds a way to talk Maynard into proposing to her, not letting him know her real plan.
Dobie can't break his heart by telling him Zelda's real plan.
Dobie tries to stop the wedding, but it's Zelda that finally admits she tricked Maynard.
But then Dobie meets Chatsworth's beautiful cousin, Pamela Osborne (Barbara Babcock) and the two immediately like each other.
Chatsworth approaches Dobie with a scheme to rig the raffle at the bazaar and split the $5000 prize.
Dobie has a fantasy about a future where he and Pamela have a lot of money from all the crooked schemes he's pulled.
Dobie learns that Maynard detained Chatsworth and his number was legitimately called.