Fitness firm Peloton has gone on the counterattack after a plot twist in "Sex and the City" sent its shares into a skid -- bringing a key character on the show back to life in a parody ad, as it seeks to revive its own fortunes on Wall Street.

In the first episode of the latest reboot of the series called "And Just Like That...," the character John Preston -- known as "Mr. Big" -- dies of a heart attack shortly after beginning a workout on a Peloton exercise bike.

Shares of Peloton suffered following the surprisingly dark turn in the comic series, falling 5.4 percent in Friday's session after the episode was broadcast Thursday night.

Peloton initially retorted with comments from a cardiologist who pointed to "Mr. Big's" hard-living lifestyle as a factor behind the unfortunate turn of events.

The doctor also cited the character's possible genetic predisposition to heart disease, while touting the merits of the exercise bike.

But on Sunday night, the exercise company came back with a more elaborate response, unveiling a new ad spot with "Mr. Big" actor Chris North, who played longtime boyfriend of protagonist Carrie Bradshaw, played by Sarah-Jessica Parker.

The ad features North sitting with Peloton trainer Jess King, who also played the instructor on the series during the ill-fated fictional workout.

In the spot, North asks his companion if they should take another ride, saying "life's too short not to."

The couple giggles as a voiceover reads Peloton's message:

"And just like that, the world was reminded that regular cycling stimulates and improves your heart, lungs and circulation, reducing the risk of cardiovascular disease. Cycling strengthens your heart, muscles, lowers resting pulse and reduces blood fat levels.

"He's alive," the ad concludes.

Shares of Peloton jumped 4.7 percent to $40.34 in early trading, but later retreated with the broader market, and was down about 0.3 percent.