In the midst of central London, a successful Indian restaurant called 'Gaylord' is run by a Londoner of Indian origin called Pinu (Vinay Pathak). A well off businessman, Pinu however, is a very insecure and under-confident man, who views his own life as a string of tragicomic moments. Ever since his parents died in a plane crash, Pinu has lived with his quirky Gujarati foster family …there's Jaisukh Kaka, his wife Kanta Kaki and Rajat, their only son. A simple soul at heart, Pinu has many complexes - a special one being that he is a virgin and has experienced no intimacy with a woman. To top that, his biggest fear is to be laughed at by people… an ever-repeating phenomenon with him. Pinu is quite an introvert and has no real friends…the closest he has ever gotten to a friendship is with his foster brother Rajat, who is quite a contrast to his own personality. Rajat is a well-built and handsome man with a casual air about him; he is also the lead singer of a rock band. Rajat is very fond of Pinu, though is often a source of annoyance to him as he finds Pinu really funny.
After a failed and humiliating experience when Pinu went to India to have an arranged marriage to a traditional girl who finally dumped him at the altar and eloped with her lover, Pinu is broken and disheartened…traumatized to have been the laughing stock of the evening. He returns to London and pretends to his staff at the restaurant that his marriage went well, except that his bride is yet to join him as she is stuck in India due to Visa issues. Hiding behind his lie, Pinu is becoming a pretty depressed guy…lonely, bored and bitter. One day, a young Indian fellow called Kamles comes to his restaurant and asks for a job as a stand-up comedian. Quite thrown off, Pinu initially refuses but finally lets him join as a cook, who also does a stand-up act in the evenings. On the same day, he hires a new cashier - Renu (Gul Panag), a young art student from India, who has a passion for caricatures. Life changes dramatically for Pinu as Gaylord begins to transform… Renu works on the look of the place, makes cheerful caricatures for customers while Kamles is a fabulous cook with a great talent for making people laugh in his acts and soon the restaurant is more happening and the business is much better. But the greatest difference they bring to his life is friendship. There is a visible difference in Pinu's personality now, as he lets himself hang out a bit with them.
One fine day, Pinu accompanies Kamles to buy a lottery ticket as Kamles is a big lottery enthusiast. Kamles insists that he buys the ticket as he has proved to be a lucky man in his life. Surprisingly, Kamles does win the lottery and as he goes to hug Pinu in his excitement, he lands an accidental kiss on his lips. Pinu is thrown in to a daze as he walks away from the restaurant that night…he has discovered a totally new fear - he might be Gay!!
Disturbed with his latest predicament, Pinu is at unease with any kind of physical contact with Kamles, and often warms up to Renu to re-affirm the feeling that he is straight. On one such occasion, when Pinu takes Renu out for dinner…they have a wonderful time together but Renu's fondness for Kamles disturbs Pinu. From the next day, he often finds himself annoyed and irritated to see them together, laughing or cracking jokes. He knows he is jealous but what alarms him, is that he is jealous of Renu for being with Kamles. Pinu seeks refuge in Rajat's advice which is quite simply - screw a woman!
On a mission now, Pinu goes on a rampage seeking available women for a sexual rendezvous. However, he only ends up suffering another string of tragicomic situations, thereby feeling humiliated and laughed at! At the restaurant, things are no better. Totally unaware that Renu is actually attracted to him, Pinu is consumed by jealousy whenever Kamles spends time with her. In a moment of weak judgement, Pinu frames Renu in a sticky situation over the accounts and fires her. Renu is humiliated and leaves. Pinu is saddened by the confusion and emptiness in him and goes back for further advice to Rajat, who tells him to get married as he would have enough time then to get over his performance anxiety. Pinu agrees to an arranged marriage again, this time to a girl who is quite clearly interested in his money and fixing her Visa expiry with her marital status as his wife. However, a compromise doesn't seem like too bad an idea to Pinu and he settles for it.
At this point in the story, Pinu bumps into Renu again. He walks along with her to her house and they end up making love. On a new high, Pinu has discovered a new man in him and is thrilled to have Renu back in his life. However, she finds out that he is marrying someone else in a week and leaves him, feeling hurt and used. Pinu is miserable and Kamles tells him that he has to get Renu back. But when he goes to her house, he finds out she has moved. Kaka and Kaki are busy with his wedding preparations and Pinu finds himself at the altar once more, miserable and heartbroken. Suddenly, Kamles comes in and announces that Pinu cannot marry the girl as he is gay!! The wedding is called off and Pinu rushes out with Kamles to meet the woman he loves - Renu.
Finally, Straight!! is a funny tale about Pinu, who struggles with himself, his fears and his complexes, to 'come out' as straight and finds true love.