: Catherine and Billy are ambushed during a routine surveillance job. Billy is mortally wounded and later dies in the hospital. McGarrett and the Five-0 team hunt for the killer, eventually tracing the hit to an assistant in a mistress's office who acted out of unrequited love.
: Joe White returns and provides McGarrett with evidence that his mother, Doris, is still alive and active. Cast Highlights Alex O'Loughlin : Steve McGarrett. Michelle Borth : Catherine Rollins. Terry O'Quinn : Joe White. Justin Bruening : Billy Harrington. Hawaii Five-0 (TV Series 2010–2020) - Episode list - IMDb Watch Hawaii Five-0 2010 S04E05
: Available for purchase or streaming via linked subscriptions. Episode Summary : Catherine and Billy are ambushed during a
: In Hong Kong, Adam Noshimuri considers making a major sacrifice to ensure Kono's safety. : Joe White returns and provides McGarrett with
In Season 4, Episode 5, titled "Kupu 'eu" (Fallen Hero) , a surveillance job for Catherine and Billy takes a tragic turn when they witness a hitman killing their subject. The episode originally aired on October 25, 2013 . How to Watch You can stream this episode through the following services: Paramount+ : Offers all 10 seasons for streaming.