Gustave has taken it upon himself to observe Marion and Sanglain following the death of the Princess and DT.   But KT thinks Gustave is in the city of Marquesas for other reasons. 
I'll stuff all your pockets 
full of potato starch!
¡te voy a llenar los bolsillos 
de almidón de patata!
voy a llenarte los bolsillos de pieles de patatas!
encher seus bolsos de amido de batata!