My Demon King from Hell

Isa Ever works at Rubiks Co as a secretary and within a short 4 years she is now the head secretary under the CEO. Popularly called as Miss Perfect, her ability is well known throughout the company. Despite the heavy workload she is satisfied because of the high pay and her kind boss. May be life thought it is being too kind to her, Rubiks was acquired by Phoenix technologies.
Her new boss is the well-known Demon King from hell, Noe Norman, cold, ruthless and the embodiment of precision. Under the lure of the high pay and the high potential of the new company she changed to phoenix headquarters, enduring his high demands and continues as his secretary.
Working together, as she discovers that the demon king is just a single layer of him, the tip of the ice berg, tension grew and sparks flew but then the past catches up like thorns on their new grown relationship. Will it grow successfully or will the thorns overwhelm it?