Mahal is based on an interesting premise. Rajesh Dixit (Dev Anand) is paid to impersonate the nephew of a rich man whom he has not seen since 18 years. Desperately in need of money, he accepts the assignment, only to find that nothing is what it seems.
It has the material for a tight, exciting thriller. Unfortunately, suspense scenes are few and far between. I confess that I didn't see the one plot twist coming, but there's little to build on it. Way too much time is wasted on the romantic angle between Rajesh and Roopa (Asha Parekh) and much too often, the flow is interrupted by a song.
With a run time of nearly 2 hours and 30 minutes, the movie outstays its welcome. Nonetheless, it has its moments. Dev Anand is his usual charming self, as is David (as Roopa's father)- the one extra star is for those two. The movie is decent and yet, it could have been so much more.
To sum it up: great idea, poor execution.