The Loyal Pin

Lady Pin, an orphaned noblewoman, is taken in by her strict but loving aunt at the Savettawarit Grand Palace, where she forms a deep bond with the mischievous Princess Anil.

Lady Pin struggles with the impending departure of Princess Anil, who is set to study abroad, leaving Pin feeling lonely and heartbroken.

Princess Anil returns home after years abroad, rekindling her bond with Lady Pin. However, new relationships and old insecurities threaten their friendship.

Princess Anil, uncertain about Lady Pin's feelings, hatches a plan to get closer to Lady Uangfah in order to test Pin's emotions. As expected, Pin becomes irritated and upset with Anil, though she conceals it.

Lady Pin distances herself from Princess Anil following a significant event. Later, Anil confesses her love and gifts Pin a gold hairpin.

Princess Anil and Lady Pin's blossoming romance at the Pine Palace faces a challenge as Anil must leave again for her studies abroad.

Lady Pin wakes from a nightmare to find Princess Anil by her side. They share a final night before Anil's departure. Despite her resolve, Pin hides to say goodbye. Anil reconnects with childhood friend Lady Aon abroad.

After returning from abroad, Princess Anil is celebrated for graduating early. Jealous of Lady Pin, she drinks too much and gets drunk. Pin takes her home, and Anil kisses her, unaware that they are being watched by someone.

During a beach trip, Mr. Kueakiat tries to woo Lady Pin, who avoids him. After saving Lady Aon from drowning, Princess Anil secretly gives Pin a diamond ring, sparking Kueakiat's curiosity.

Mr. Kueakiat hurries to approach Princess Patthamika after noticing the ring on Lady Pin's finger, which raises her suspicions. Meanwhile, Princess Anil needs to prepare for her master's degree studies as decided by Prince Anan

Princess Anil, Lady Pin and others travel to attend a royal banquet. Lady Uangfah confesses her forbidden love to Anil. Pin performs a dance with Uangfah, then secretly meets Anil, giving her a ring and a kiss.

Princess Patthamika arranges Lady Pin's engagement to Mr. Kueakiat, but Princess Anil intervenes, declaring that only she truly deserves Pin.

Princess Anil tries to stop the wedding, but Lady Pin chooses to engage Mr. Kueakiat herself. Anil feels betrayed and distances herself. Seeking solace, she turns to Lady Uangfah, leaving Pin heartbroken.

Princess Anil avoids Lady Pin. Despite Pin's attempts at reconciliation, Anil stays resolute, even considering to move abroad. Later, Anil discovers Mr. Kueakiat has a pregnant wife, yet Princess Patthamika insists on the wedding.

The wedding is abruptly interrupted by a mysterious woman. Princess Anil returns to Lady Pin, and they vow never to be apart again. Meanwhile, His Royal Highness is left speechless upon realizing Anil's love for Pin.

Princess Anil asks her father for permission to be with Lady Pin without getting married, which displeases him. However, their unwavering love, along with the support of Princess Alisa and Prince Anan, eventually makes him to take action.