Mikami Satoru, a businessman, is stabbed by a criminal on the street and killed. When he regains consciousness in the darkness, he finds that he's been reincarnated as a slime! With nothing better to do, he spends his time devouring all the rare herbs and precious ores he comes across. As he does, he encounters the Storm Dragon Veldora, who was sealed in this cave 300 years ago by a hero's "Unlimited Imprisonment" skill. He's frightened at first, but as they talk, he becomes friends with the long-isolated Veldora.
So you've been in here ever 
since that hero sealed you?
إذاً كنت هنا منذ أن ختمت عليك تلك البطلة؟
Und Ihr wart die ganze Zeit hier,
seitdem ihr versiegelt wurdet?
¿Y llevas aquí
desde que el héroe te selló?
¿Y llevas aquí
desde que el héroe te selló?
Et depuis qu’elle t’a scellé,
E quindi
Então, essa heroína te selou aqui
e é onde está desde então?
Значит, вы здесь с тех пор,
 как герой запечатала?