Kohaku has located the treasure left behind by Byakuya and the others, but it's encased in concrete. Senku has to devise a plan to quietly get at the contents inside, so as to not alert the guards.
Just leave it in there for a while, 
and it'll mix in the hole and make plaster.
.اتركيها هناك لبعض الوقت، وستختلط في الحفرة وتصنع جصًّا
Jetzt nur noch warten.
Solo hay que esperar
a que se mezclen dentro
Solo hay que esperar
a que se mezclen dentro
Maintenant, on patiente.
Basterà lasciarle dove sono,
Só deixa mais um tempo, e vai 
misturar no buraco e fazer um gesso.
Через какое-то время внутри
всё смешается — и получится гипс.