When Rooky discovers it's Chief Wheeler's birthday, she is determined to make it memorable. During the dedication ceremony of the city's deep sea vessel to honor Duke, Freya and Harl, the ship is accidentally set adrift.
Duke and his temperamental smart car learn each other's ways to catch the Ice Cream Truck Bandits. The oblivious Ms. Blumfeld turns into a superhero, stopping crimes around the city, as Duke struggles with his orders to arrest her.
Fendrich organizes a charity as a distraction while he attempts to steal the city deed. Sinclair gathers antiheroes to stop him. Freya is one credit short of graduating from the fire academy and is suspended as Fire Chief.
Officer Duke DeTain patrols without a partner on Christmas Eve. Astronauts reach Mars orbit and prepare to launch their probes; Tippy Dorman puts his own plans into motion to secure a large Mars rock that looks remarkably like a door.
We pull back the curtain to see how Firemen Bob and Clemmons retrieve the bizarre requests of Chief Freya during a typical emergency. It's an old west showdown, when a new adversary rolls into town.
Mayor Fleck is running for re-election against R E Fendrich who will stop at nothing to win to use his new power to defeat Sinclair. When Duke loses his memory, Snake Rattler tricks him into believing he's Snake's criminal henchman.
A movie promotion stunt goes wrong, unleashing a humongus "Cubby the Cop" balloon on the city. Fire Chief McCloud accidently buys a malfunctioning Twirly Hat for her nephew.
It's Harl Hubbs Day and Harl decides to help the whole city, but quickly discovers he isn't prepared for Harl mania; Billy's mother, Ann, accepts a junkyard race challenge against the city's street racing legend, Tread Octane.
Police Chief Wheeler announces the formation of the 700 million dollar Sky Police. Police captain, Tom Bennett, gets a call that his wife has gone into labor early.