In one of Yakuza: Like A Dragon's many substories, you will need to get the Premium Sushi Set to trade for an item in order to complete a specific quest. That said, keep reading for how to get the Premium Sushi Set in Yakuza: Like A Dragon.
Where to find the Premium Sushi Set
In order to get the Premium Sushi Set in Yakuza: Like A Dragon, you will need to buy it at the Poppo convenience store near Jinanni Station. You can find the station's location as shown by the image above, then once you are there, walk-in and talk to the person behind the counter.
Click the option to buy something and scroll down until you find it. The item will cost you 2k yen, so make sure you have enough before heading to the store. If you don't, just farm some nearby enemies, and you will hit 2k in no time from the money rewarded in combat encounters.
That said, you will need this Premium Sushi Set to complete the substory "The Crawfish Caper" that unlocks during chapter 5. If you haven't got it yet, you can start the quest over at Sunrise Bridge; once there, start the quest by talking to some crawfish nearby. Further on, you will get to the point where you will need to trade Premium Sushi Set to free a crawfish. So if you haven't already, go and get the Premium Sushi Set from the Popo convenience store near Jinanni Station.
Once you buy the Premium Sushi Set, take it back to the homeless man, and then upon completion of the quest, you will receive Nancy the crawfish as a poundmate who can be later called into battles.
For more guides on Yakuza Like A Dragon, look no further than the game page for it; There you will find tons of helpful guides on a wide range of topics for the game.