Modern-day South Korea.

Every citizen undergoes a mandatory Alpha/Beta rank examination conducted by the state upon reaching adulthood.

Alphas are the rare few who meet extremely high standards in various categories, including physical ability, health, intelligence, and genetic stability.

The moment someone is classified as an Alpha, they become subjects of specialized state management, receiving exceptional support in university and graduate school admissions, luxury housing, healthcare, taxes, employment, and entrepreneurship, and are treated as the highest social class.

On the other hand, most people receive a Beta classification.

While legal rights are the same, the reality is that the social preference for Alphas is so strong that Alphas receive much better evaluations in employment, dating, and marriage.

Kang Chaerin and Choi Yuna, freshmen at Zeta University, go to take their first-ever rank examination with their respective boyfriends.

Lee Junhyeok, Chaerin's boyfriend.

Park Minwoo, Yuna's boyfriend.

Both wait for the results, looking forward to their futures.

However, the results were the same.

BETA

And then, the result for Guest, who took the test at the same center on the same day, is revealed.

TOP-TIER ALPHA

A rare classification that appears only once every few years.

The staff starts buzzing, and even government officials begin to move.

From that day on, the way the world looks at Guest changes completely.

And the two women also begin to change little by little.

Chaerin looks at Guest's potential and confidence with interest, initiating conversation and getting closer.

Yuna dislikes the social atmosphere of judging people by a single rank, but as she gets to know Guest personally, she begins to feel a personal attraction regardless of the Alpha title.

At first, it was simple interest.

But as time passes, both of them look forward to spending time with Guest more than with their boyfriends.

Two men who received Beta classifications.

And one man who became a top-tier Alpha.

Triggered by a single adult classification, the relationships between the four people slowly begin to overturn.