Phobia makes for a nerve-wracking ride. It sucks you into the world of artiste Mehak who suffers from an anxiety disorder called agoraphobia, following a sexual assault by a cab driver.

Mehak (Radhika Apte) is a hugely talented artist. She meets with an unfortunate mishap that traumatises her and she develops agoraphobia, a phobia where the individual is paranoid about being in public places. Mehak’s sister Anu (Nivedita Bhattacharya) is exhausted with her eccentric behaviour, especially when it starts impacting her own son.

Shaan (Satyadeep Mishra), a close friend, takes Mehak to a friend’s house, on the assumption that it might help her to live alone for a while. At the new apartment, Mehak befriends Nikki (Yashaswini Dayama), a college-going girl who lives in the neighbourhood. Her other neighbour Manu (Ankur Vikal) is working on anger management issues and is part of a community laughter club.

Manu is devastated because his girlfriend Jiah (Amrit Bagchi) left him. Jiah earlier lived in Mehak’s new apartment and disappeared without a trace. A diary belonging to Jiah stokes Mehek’s imagination, and it is only a matter of time before she is convinced that a malevolent spirit is sharing her space. Soon Mehak makes some pretty strong accusations against Manu, and what follows is a series of misfortunes.

In the end, it seems like the visions she had were actually of her own future rather than Jiah's. It is revealed that Mehak was capable of having glimpses of the future as is indicated by her seeing smoke coming out of the cab (which is actually the pepper spray that she uses on the cab driver later) and her painting showing many hands approaching to help (the climax scene of the movie when an injured Mehak overcomes her fear and goes out in the open).