Same Unique character on same side

By GioKarab, in 2. AGoT Rules Discussion

Hello,

If i have a unique character and i take control with say Horn of dragons the same unique character from my opponent, what happens exactly?

GioKarab said:

If i have a unique character and i take control with say Horn of dragons the same unique character from my opponent, what happens exactly?

"Each player may only have one copy of a unique card in play. Thus, you cannot put into play or take control of a unique card which you already own or control." -- p.19 of the rule book

Thanx again bro :)