On Dynasty, presumed-dead heiress Fallon Carrington Colby (Emma Samms) reappears alive, suffering from amnesia and using the name Randall Adams.

A mutual business venture brings the Colbys of California to the Denver mansion of Fallon's father Blake Carrington (John Forsythe).

There were initially a number of crossovers featuring members of the Dynasty cast, most notably Blake Carrington, his sons Adam and Steven, and half-sister Dominique Deveraux.

At the end of the season, Fallon learns that Miles could be the father of her unborn child, Monica's plane crashes, and Sable has Jason arrested for assault and battery, claiming that he had inflicted the injuries she actually sustained by falling down a flight of stairs.

Previously romantically linked to both Zach's nephew and former stepson, Bliss falls in love with a Russian dancer watched by the KGB, the son Monica had given up eight years before re-enters her life, and Constance and Hutch are killed in a plane crash in India.

[3] Sable (now divorced from Jason, who was still involved with Frankie, who survived the car crash) and Monica (who no longer had contact with ex-lover Cash or their son Scott) also later reappeared on Dynasty for the series' ninth (and final) season in 1988–89.

[4][5] Dynasty actors Rock Hudson, Ali MacGraw, Jack Coleman, Heather Locklear, and John James were mentioned as potential stars of the new series, tentatively titled The Colbys,[4][5] and ABC was purportedly wooing Pamela Sue Martin to reprise her role as Fallon Carrington.

[17] In August 1985, producers cast British actress Stephanie Beacham, "a household name" in the UK who had starred in the title role of the ITV drama Connie.

[25] The 13 bedroom, 15,000 sqft[26]Jay Paley House in Holmby Hills (at the time owned by business magnate Barron Hilton) featured as the family palatial Bel Air mansion, The Belvedere.

[citation needed] The Colbys premiered at 10 pm on Wednesday, November 20, 1985, after Dynasty's eighth episode of the season, and was initially a ratings success.

[27][28] The next episode of The Colbys was scheduled to air the next night, Thursday, November 21, in the show's own new time slot, but was preempted by a televised speech by US President Ronald Reagan.

[33] The same month, Ron Miller of the Evening Independent suggested that The Colbys "appears to be so prohibitively expensive that future payoff in syndication seems very chancy.

[35][36] In December 1986, it was reported that Heston had sent co-star Caulfield a letter admonishing him for unprofessional behavior on set, while calling the rest of The Colbys team "the best I've worked with in 30 years.

[25] Lee Margulies of the Los Angeles Times wrote, "It's not a spin-off, it's a clone—as close a replica as ABC and the Dynasty producers could concoct, right down to the credits.

"[25] In their Directory To Primetime TV Shows, television historians Tim Brooks and Earle Marsh stated that the series likely failed because it was "too close a copy" of Dynasty.

[48] When Stanwyck opted to end her contract and leave the series after its first season in 1986, she reportedly called the show "a turkey",[49] and told co-creator Esther Shapiro "This is the biggest pile of garbage I ever did" and that "It's one thing to know you're making a lot of money off vulgarity, but when you don't know it's vulgar—it's plain stupid.

"[51] Dynasty star Joan Collins categorically refused to make any appearances in The Colbys herself, believing it would have caused "massive confusion between the two shows".