Season 1990, Episode 1: Columbo Cries Wolf - Publisher Dian Hunter stages her disappearance with partner Sean Brantley for publicity, only to genuinely vanish when she still plans to sell her share of their men's magazine. Columbo, initially misled, realizes Brantley committed the real murder after the "cried wolf" hoax. The detective ultimately exposes Brantley by locating Dian's body hidden in a wall, alerted by her pager, and sending a final "GOTCHA" message to the device.

Season 1990, Episode 2: Agenda for Murder - Ambitious attorney Oscar Finch murders blackmailer Frank Staplin, staging it as suicide to protect his political career. Columbo uncovers inconsistencies like a cigar smell and chewing gum. The detective ultimately exposes Finch's guilt by revealing a critical piece of evidence related to a small bite of cheese, proving his presence and leading to his irreversible downfall.

Season 1990, Episode 3: Rest in Peace, Mrs. Columbo - Vivian Dimitri, seeking revenge for her husband's death, murders her boss, Charlie Chambers. She then attempts to poison Mrs. Columbo. Columbo stages a fake funeral, prompting Vivian to confess her crimes. Columbo reveals his wife is alive and he knew her plot,

Season 1990, Episode 4: Uneasy Lies the Crown - Dentist Wesley Corman, facing divorce and gambling debts, murders his wife's lover, actor Adam Evans. Corman places digitalis in a dental crown, then frames his wife, Lydia, for Evans' fatal heart attack. Columbo exposes Corman by demonstrating that digitalis would leave a blue stain on a porcelain crown, a chemical fact the dentist is unaware of.

Season 1990, Episode 5: Murder in Malibu - Romance novelist Theresa Goren is found dead, initially appearing to be a robbery victim. Her philandering lover, Wayne Jennings, confesses to shooting her with her own gun after she broke off their engagement, but an autopsy reveals she was already dead from a different caliber bullet, seemingly clearing him. Columbo ultimately deduces that Jennings killed Theresa earlier and then staged a second shooting to mislead investigators. The critical reveal is that Theresa's underwear was on backwards, indicating Jennings clumsily dressed her body after the initial murder to create a false narrative.

Season 1990, Episode 6: Columbo Goes to College - Criminology students Justin Rowe and Cooper Redman murder their professor, D.E. Rusk, to prevent expulsion for cheating. They use a remote-controlled gun during Columbo's guest lecture, believing they've created a perfect crime and can outwit the detective. Columbo ultimately exposes them by recreating the murder and revealing they planted the murder weapon in Mrs. Columbo's car, a detail only they knew. The arrogant duo is arrested, stating they committed the crime "because we knew how to do it."