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.
Ever since then, I've had nothing 
to do, and it's unbearably boring.
ومنذ ذلك الحين وأنا لا أفعل شيئاً، وهذا
مملّ للغاية
Seitdem hatte ich unglaublich
viel Freizeit und entsprechend Langeweile.
Desde entonces,
he estado muy aburrido aquí.
Desde entonces, vivo muy aburrido aquí.
Depuis, je n’ai rien à faire
et je m’ennuie tellement…
e da allora non ho mai avuto niente da fare
e mi sono sempre annoiato a morte.
Desde então, não tenho nada pra fazer,
estava muito, muito entediado.
И с тех самых пор я каждый день
маялся от непереносимой скуки…