Complete Horizon wrote...
English, motherfuckers.
Hai. Watashi no keikaku wa kekkan nashi deshita.
Literally translates to: "Yes. My plan was without flaw."
@ryssen Just take Japanese 101 or any free online classes...
Constructing sentences like this is one of the first things you learn after learning hiragana and katakana.
Though mine uses kanji because I know what kanji to use, because of the last 2 years of uni classes, you can use just hiragana and it would be fine.
It's a simple sentence and the context is clear so anyone who understands the language would understand if they read it.