Liang Xia has given up a promising career as a talented painter to be a perfect, attentive girlfriend for her "Prince Charming," who she assumes will propose to her soon, but she is constantly disappointed as Mao prioritizes his work at a design agency over her.

While morosely watching TV one morning, Liang sees an infomercial for "magic" chocolates that purport to grant youthful energy, and orders a box on a whim.

When she regains consciousness several seconds later, her mind, memories, and personality have been replaced by those of her 17-year-old self, who is perplexed to find herself 11 years in the future.

Big Liang and Bai, theorizing that it was the car crash that triggered the transformation, bribe a taxi driver to rapidly accelerate and decelerate, but are caught and detained by police.

One night, Little Liang goes camping in a tent with Yan, but freezes up and pulls away when he kisses her neck; she nervously explains that she is a virgin.

She records a voice message begging the more romantically experienced Big Liang to physically reciprocate her attraction to Yan on her behalf, promising to paint her designs in return.

Just as she reverts to Big Liang, Mr. Gao puts her on the spot, presenting her with an empty canvas and asking her to demonstrate her talent for spontaneity for a live audience.

Liang, who is sitting in the back seat, tells him that she doesn't blame him, but no longer wants to linger behind him waiting for him to turn around.

Little Liang, in a final act of desperation and over Bai's protests, consumes all nine of the remaining chocolates at once, hoping to stay in her current form long enough to win back Yan.

The unconscious Liang is rushed to a hospital, where she begins to flatline as doctors diagnose her as overdosing on an unknown substance.

Some time later, Yan is biking in a different city when he looks up, seeing a digital billboard showing an advertisement featuring one of Liang's designs.