From the very beginning, (Y/n) swore her loyalty to Daisuke Kambe at the age of 5. The (L/n) family acts as the sword and shield, protecting the family members with everything they have. She promised she'd do everything to protect him, and she kept that promise for 19 years. Through thick and thin, (Y/n) was there, protecting him from everything she could. Now, her superior wanting to go back to Japan, (Y/n) goes with him. But, will she be able to protect him forever like she promised?