To readers that do not understand the joke: in a fan translation of the anime Death Note, the translator decided to translate the line "Just as planned" as "Just according to keikaku" with a translators note above it, saying that keikaku means plan. While back in the day, japanese words were often included with translators notes, this wasn't needed here and obviously a joke. This was only done when the word carried special meaning that couldn't be accurately translated using english words. Honorifics like -san or -sama were prominent examples.
(I kinda miss the times when common japanese words were not translated. Current translations often look weird (esp honorifics) and since the rise of Crunchyroll and subsequent demise of fansubs, there isn't much choice left for different translations)