[6] Nine strangers from the city gather for a 10-day retreat at Tranquillum House, a health and wellness resort in the fictional town of Cabrillo, California,[7] which promises to transform and heal the guests who stay there.

[14][15][16] In the second season, Masha will lead a fresh ensemble of nine strangers, who seek sanctuary from their hectic lives with a 10-day stay at a resort nestled in the Swiss Alps.

[21][22] In July 2020, Melvin Gregg, Samara Weaving, Grace Van Patten, Tiffany Boone and Michael Shannon joined the main cast.

[6] On December 14, 2023, Liv Ullmann, Murray Bartlett, Annie Murphy, Christine Baranski, Dolly de Leon, Maisie Richardson-Sellers, King Princess, Aras Aydın, and Lucas Englander were cast as series regulars for the second season.

All actors were required to quarantine for fourteen days in the city of arrival in Australia, due to regulations imposed by the Australian government in response to the COVID-19 pandemic.

The critics consensus reads, "A meandering mystery may muddle its impact, but strong performances across the board from its eclectic ensemble mean Nine Perfect Strangers is never less than watchable.

[47] Alison Herman of Theringer pointed out one of the biggest mistakes of the show was that it followed the HBO's big hit The White Lotus "too soon" and was "overstuffed and undercooked".

[48] Alexis Nedd of Mashable compared the show to "smoothies" and commented that "the individually good pieces are some wonderful performances, an interesting premise, and a visually stunning location.

"[49] Make a comparison to the previous hit show Big Little Lies, which combined the same elements as Nicole Kidman starred based on a best-selling novel from Liane Moriarty and adapted by David E. Kelley, Rachel Cooke of New Statesman called out "this time around, however, the glossy algorithm has failed to work.

[50] Kevin E G Perry of The Independent called out "the stellar cast's obvious chemistry helps elevate a script that grows increasingly melodramatic as each of their character's secrets are brought to light.

"[51] David Bianculli of NPR praised the performance of leading lady Nicole Kidman as "it's yet another deep and challenging role she's inhabited since opting to focus on TV miniseries as well as movies" even though it "is more of an ensemble than a solo turn.