Lost Expedition was a mission on Spineworld.
Professor Bongo wants to look for the missing Bongo expedition. He has a letter in a scroll he wants to give to them.
Go to Airtram Station and take the airtram to Meyan Temple. Walk down to the Bongo Camp, which turns out to be the missing Bongo expedition. Talk to Ma Bongo and she will write a reply to Professor Bongo's letter, then go back to him.