The actress told Entertainment Weekly that "people are dying left and right" in the Syfy drama's second run.
"They're getting killed, things are happening, and there's a lot more gun play this year," she revealed. "It's... a bit heavier this year. Last year, we were able to get drawn into the town and the quirkiness of the characters, and this year, we're dealing with weightier topics."
However, Rose insisted that she will "always have an affinity for the quirkiness" of Haven.
"I like the silliness and the banter," she admitted. So I'm always rooting for that to stay in the show... but I'm excited we were given the permission to go deeper and darker than we did last season. It takes us to another level."
Haven star Eric Balfour previously revealed that his character Duke Crocker will get a new love interest in the second season.
"There's a character who comes in this season that really pushes Duke's buttons," he confirmed. "That's not something you got to see a lot of last year."
Syfy originally renewed Haven for a second season last October. Beverly Hills, 90210 star Jason Priestley, Being Erica's Vinessa Antoine and WWE star The Edge have all signed up to appear in the show.
The second season is scheduled to begin on July 15 at 10/9c on Syfy.
> Cristián de la Fuente lands Haven role
Watch a clip from Haven's second season premiere below: