Viewers can watch the TV series "Castle" on Hulu.com, Vudu.com and Google Play. Hulu offers the four most recent episodes for free and the rest of the latest season for paying Hulu Plus subscribers, while users can purchase individual episodes or full seasons on Vudu and Google Play.
In addition to select full episodes, Hulu provides free "Castle" clips, interviews and behind the scenes features. Google Play allows users to purchase episodes from all of the seasons and write reviews. Vudu also features episodes from every season along with short plot descriptions for each episode. Users purchase episodes or full seasons in standard- or high-definition.