We pick from the last episode where we saw the Straw Hats getting excited about the reaching Raftel with the help of Road Poneglyph.
Nekomamushi tells them that there are four of them in total. One of them is in Zou. The Yonkō, Big Mom and Kaido have one each. The location of the last one is still unknown. Nekomamushi also told them that they can just copy what is written on the Poneglyph with ink and regular paper. He also voices concern for Nico Robin as she is the only person alive who can read the Poneglyphs.