Side Effect

Alpha Kwon Yi-Hyeon hires Yu Bom, a secretary who matches his tastes. Yi-Hyeon is taken aback when he discovers that Bom, whom he thought was an Omega, is actually a Beta. After obtaining a drug through an acquaintance, Yi-Hyeon attempts to force Bom to manifest as an Omega...

(Source: MrBlue, translated)

Note: Includes two extra chapters.