Basically, you need to "talk" to the general there, and the entertainment on the bridge is not fully available yet, so you can not do them yet. Right now you can only open 3 castles on the map, but they are useless yet.
And if you want to open these locations, you need to leave at least one monster from the location for battles on Celica's body, and surrender to the shadow character, and when the shadow character considers himself the winner, kick him out. This must be done 3 times, each time observing the appearance of a new location on the map.