I didn't rent Hannah Montana: The Movie, but I watched it on Youtube. It does technically have a plot, but it's pretty flimsy. I'd say the plot is flimsy in the same way that the plot of "Help!" by The Beatles is flimsy, even though the two films have a very different feel.
Plot is as follows (warning, spoilers):
Miley and Lily sneak past security at the stadium where Hannah Montana has a concert, and get to Hannah's dressing room. Miley changes into Hannah Montana and does her concert.
A few days later is Lily's 16th brithday, and she has planned a giant party. Miley has to go shoe shopping as Hannah before the party. At the shoe store, Miley gets into a fight, and draws the attention of a magazine reporter. The magazine reporter follows Hannah when she leaves the shoe store. Because she is being followed by the magazine reporter, Miley can't change out of her Hannah costume, and has to go to Lily's party as Hannah. Lily gets upset that Miley came to her birthday as Hannah, and refuses to enjoy the rest of the party.
Later, Miley tries to phone Lily, but Lily won't answer, because she's mad at Miley. Miley's dad Robbie is also mad at Miley because of Hannah's fight at the shoe store. Robbie wants Miley to take a break from Hannah, and wants Robbie, Miley and Jackson to go to their hometown of Crowley Corners Tennessee for two weeks, a trip which will include Hanna's Grandma's birthday. Hannah has an awards show appearance in New York which Robbie wants Miley to miss. One of Hannah's handlers says they can take a private jet to New York, Hannah can do her awards show appearance, and then they can fly to Tennessee in time for Hanna's Grandma's birthday.
Robbie, Miley, and Jackson get on Hannah's private plane, headed ostensibly for New York, but Robbie secretly orders the pilot to fly to Tennessee instead. When they get off the plane in Tennessee, Miley protests not being allowed to go to Hannah's awards show appearance in New York. A pickup truck awaits to take them to the grandparent's farm.
Halfway to the Grandparent's farm, Miley orders her dad to stop the truck, and insists on going back to the plane to New York. Robbie won't turn the truck around, and takes off without Miley and her luggage. Miley realises that she doesn't have time to get back to the plane and get to New York for Hannah's awards show. Miley takes off her Hannah wig, and then walks the remaining mile to her grandparents house.
Once at the grandparents house, Miley takes to the country life. She partakes in singing country music with the family, helps out on the farm, and gets reacquainted with an old childhood friend named Travis, who's working for the summer on her grandparents farm. They celebrate Miley's grandma's birthday, which ends in disaster when Robbie knocks over the hutch full of Grandma's collectible china plates.
When Miley and her grandmother take produce from the farm to the local farmer's market, they learn that a wealthy developer wants to build a shopping mall in Crowley Corners. The townsfolk don't want a mall in their town (which would ruin it's small town feel), so they organize a hoedown to raise money to buy the land where the developer wants to build the mall. Miley sings Hoedown Throwdown at the hoedown.
The hoedown doen't raise nearly enough money to keep the developers from building their shopping mall. The townspeople realize they can only raise enough money if they can get a major pop star to come to town for a benefit concert. Miley mentions that she knows Hannah Montana, and plans are put in place for a Hannah Montana benefit concert.
In order for it to look like Hannah is coming to Crowley Corners rather than already being there, Lily shows up in Hannah Montana's tour bus, dressed as Hannah (Lily stops being mad at Miley when Miley needs this favor).
Travis asks Miley on a date, and Miley says yes, because she really likes Travis. However it turns out that Hannah is scheduled to attend a large banquet at the same time as Miley and Travis's date. Miley tries to pull the old switcheroo routine whereby she switches back and forth between Hannah's banquet and Miley's date with Travis. The plan backfires when Travis finds Miley changing from Hannah to Miley. Travis tells Miley he doesn't want anything to do with her (though he doesn't blow her secret).
The next day Hannah goes on stage for the benefit concert, but stops partway through the first number and says "I'm sorry, I can't do this. Not here." She takes off the Hannah wig, reveals to the whole crowd that she is Miley, and sings "The Climb".
It looks like Hanna's career is over, but Miley convinces the townsfolk not to blow her secret to the rest of the world. The magazine reporter from the beginning of the moive, who has gone to Crowley Corners to cover the benefit concert, takes some more convincing to not blow Hannah's secret, but he eventually agrees not to at Robbie's urging. Travis agrees to give Miley a second chance.
End of Movie
