Bhavishya heard Karan and Laxmi and realized that she has been kept in the purani kothi. But maybe the plan isnt ruined yet, and Bhavishya hearing all this was part of Karan's plan?
He may have known very well that Bhav was hearing what he was saying, and Laxmi probably isn't aware of this secret plan... with her overflowing emotions Karan probably knew better than to tell her. But Karan may have known that Laxmi would keep giving looks to Bhav, making him suspicious, and leading him to the kothi. And conveniently Karan isn't picking up his phone either, so Laxmi can't contact him without going there herself... thus leading Bhav there. And somehow I feel he has a plan to trap him once he has him there.
I'm pretty sure it is something like this aftera dialouge Karan said to Laxmi yesterday. He told her that they would trap Bhav by playing mind games with him and making him believe that he has won, but just when he begins rejoicing... they will catch him red-handed and expose him.
Hope this prediction is true and they move on fast to a different track, can't wait to see something new!