According to TV Guide:

. . . The usually straight-laced Grover will steal from McGarrett’s playbook when his daughter is kidnapped in the season finale. “As renegade and out of control as [Grover] thought McGarrett was in the [season premiere], he goes even further in this one,” executive producer Peter Lenkov says. “He doesn’t have a free pass like Five-0 does, so there’s going to be consequences. [But] sometimes you have to turn the badge around to get the job done.” Fortunately, I hear the consequences have a silver lining that will play out next season. . . .

PLEASE let Grover join Five-0. I would love to see him and Steve together. That way SC could leave even more. I have heard he has a new movie role for later this year. I would be jumping for joy about this.

In case you wondered about the review for 4.19 – it will come later this week.