Twoson is a rather large town, although not as large as Fourside. This is where Ness can rent a bike, although it becomes useless once Paula joins your team. You can use the stores here to update your equipment at the department store, sleep at a hotel, order a pizza, and ride a bus that brings you back to where you started. This is also where Ness first meets the Runaway Five. Paula's home, the Chaos Theater, the Twoson-Threed tunnel, and Burglin Park are areas of notable interest. People of interest are Paula's father, Mr. Everdred, and the Runaway Five. There are battles available south of Twoson, on the way to Threed, but they are optional.
Twoson connects to Threed through a tunnel filled with ghosts. Until the Runaway Five are freed from they're debt, you can't go to Threed.