Trader's Adventure is a timed event where you can win rewards by collecting Trade Tokens. You can collect Trade Tokens by completing orders (merchant, cargo and/or tavern orders). As you collect more Trade Tokens, you will rise through trader levels and each level you reach will grant you a prize.
Also you can buy the Gold Pass to get more prizes from the Trader's Adventure. Buying Gold Pass also provides you with such benefits as holding more energy, faster energy recharge, more backpack space, faster cargo ships, a gold frame to adorn your profile picture and a gift you can give your clan members. Moreover, when you complete all the tiers and reach to the end of Trader's Adventure with Gold Pass, you can receive a final big reward; the Grand Treasure!