Barry Egan is a single man who owns a company that markets themed toilet plungers and other novelty items. He has seven overbearing sisters who ridicule and emotionally abuse him regularly and leads a lonely life punctuated by fits of rage and anguish. In the span of one morning, he witnesses an inexplicable car accident, picks up an abandoned harmonium from the street, and encounters Lena Leonard, a coworker of his sister's, Lena having orchestrated this meeting after seeing him in a family picture belonging to his sister Elizabeth.
Coping with his loneliness, Barry calls a phone-sex line, but the operator attempts to extort money and sends her four henchmen, who are brothers, to collect. This complicates his budding relationship with Lena, as well as his plan to exploit a loophole in a Healthy Choice promotion and amass a million frequent flyer miles by buying large quantities of pudding. After Lena leaves for Hawaii on a business trip, Barry decides to follow her. He arrives and calls one of his manipulative sisters to learn where Lena is staying. When his sister starts abusing him again, Barry snaps and demands she give him the information, which she does. Lena is overjoyed to see Barry, and they later have sex. At first, Barry explains that he is in Hawaii on a business trip by coincidence, but he soon admits that he came only for her. The romance develops further, and Barry finally feels some relief from the emotional isolation he has endured.
After they return home, the four brothers ram their car into Barry's, leaving Lena mildly injured. With his new-found freedom from loneliness in jeopardy, a surprisingly aggressive and poised Barry adeptly fights off all four of the goons in a matter of seconds, using a tire iron as a weapon. Suspecting that Lena will leave him if she finds out about the phone-sex fiasco, Barry leaves Lena at the hospital and tries to end the harassment by calling the phone-sex line back and speaking to the "supervisor", who turns out to be Dean Trumbell, who is also the owner of a mattress store. Barry travels to the mattress store in Provo, Utah, to confront Dean face to face. Dean, at first trying to intimidate Barry, finds Barry much more intimidating and Barry compels Dean to leave him alone.
Barry decides to tell Lena about his phone-sex episode and begs her for forgiveness, pledging his loyalty and to use his frequent-flier miles to accompany her on all future business trips. She readily agrees, and they embrace happily. Lena approaches Barry in his office while he plays the harmonium. She puts her arms around him and says, "So, here we go."

Question: Why did Barry buy so much pudding?
Answer: to get frequent flyer miles
Alternative answer: To amass a million frequent flyer miles.