Mission is accepted by an NPC called Sansan located in Totori Village west of the Hidden Mist village. You're tasked with finding 3 gold bars thrown in bodies of water around the mist village. After recovering the 3 bars of gold you must then bring them back to Sansan.
Gold Locations
1.The Fountain next to the Scroll Shop
2: The pond in front of the Chunin Registration Building
3: Inside the Fish Market