You don't unlock, Blackthorn city. You go through the Ice path and then your there.
blackthorn city in the move mans house
You need to get through ice path look on youtube for that
I recommend you train in the grass right below the city blackthorn
you hve to beat the blackthorn city gym in order to get back there.
You go to Blackthorn City and you go to the move tutor house there and then you talk to the man and he teaches your Feraligatr Hydro Canon. You can also learn the moves Frenzy Plant and Blast Burn from that man.
it is in blackthorn city
Blackthorn city
blackthorn city
Go in the gym.
in blackthorn city.
Blackthorn city
In Blackthorn city. In one of the houses there.
in blackthorn city
In Blackthorn City a surf behind the city's gym.
in the back of blackthorn city their is a cave where they are found
Go to the Move Deleter in Blackthorn City.
The dragon's den in Blackthorn city