It has been reported that "Penny Dreadful" has been cancelled and will not be getting a fourth season given that the season 3 finale already killed off the main character, Vanessa Ives (Eva Green) and gave each character a fitting conclusion. However, a report from Game N Guide suggests that a spin-off may be in the works.

According to the report, Vanessa had been grooming Catriona (Perdita Weeks) to become her successor and this means Catriona might eventually become the main character if a spin-off is indeed given the green light to enter production and release. 

In regards to a new setting, season 3 did see Mr. Lyle (Simon Russell Beale) head off to Egypt. In the interview with series creator John Logan this decision was intentional as Egypt promised hope and freedom for Lyle, given that it was hinted he may find a more comfortable life as a gay man in Egypt than he would back home in Europe. 

Together this would invite a possible spin-off set in Egypt where Catriona gathers a new cast of allies to continue battling dark supernatural forces and occasionally encountering characters from the original show such as Mr. Lyle or even some old villains that may have survived.

As for the main show potentially getting renewed for a fourth season, Logan explained that the decision to end it was final and had been conceived some time back.

"The show, to me, has always been about Vanessa Ives and her struggle with faith. I knew, sooner or later, it would get to a point of apotheosis, where she would either accept her God or deny her God," he explained, revealing that her death and acceptance of God had completed her story arc and that there would be no reason for a fourth season without her.

Showtime has yet to confirm or deny if there is a possibility of a spin-off happening anytime soon.