Hawaii Five-O is a thoroughly entertaining reboot of a TV series originating in the late '60's.
NCIS, and NCIS: LA are two thoroughly entertaining US crime dramas which evolved out of JAG and have a similar feel to CSI.
Daniela Ruah stars as an agent in the LA branch of the Naval Criminal Investigative Service but will be visiting Hawaii in the new season starting September in the US. Yes, folks, we have a NCIS / Hawaii Five-O crossover! It makes sense, I guess as Hawaii does house a pretty significant naval base...
We know this is going to happen because Daniela Ruah tweeted the following from her personal account:
Aloha hoaloha! Read my lips closely... Kensi will make her way to Hawaii Five-0 this season! Stay tuned... #H50 #NCISLA
One presumes, given the two shows and this event that the crossover episode(s) will have plenty of bang for your buck.