Roller Coaster

Pure meets up with friends at her regular bar and unexpectedly runs into Air, her former lover. She quickly goes over to greet her, only to find that Air has brought along Loft-the younger sister of Lamp, Air's husband. From their very first meeting, Loft is instantly drawn to Pure and suspects that Pure and Air may have been more than just friends. Later, by chance, Loft runs into Pure again and invites her to a restaurant to get to know each other better. Pure begins to feel a sense of warmth and comfort having Loft in her life, yet she still finds herself waiting for Air's return. Meanwhile, the relationship between Lamp and Air begins to waver under family pressure for them to have a child together.

Loft tries to get closer to Pure by joining her ceramic class and secretly buys one of her paintings for his mother. There, she runs into Air's mother, Juthamas, who grows suspicious when she recognizes the pen name PureProud-the same as her daughter's ex. At the same time, a wealthy patron, Khun Jay, commissions Pure's painting and asks her to deliver it in person. Believing the buyer is Loft, Pure agrees-only to realize the event she walks into is none other than Lamp's birthday party.

Air and Lamp left for their honeymoon in France, leaving Pure without seeing them for several days. During that time, Pure felt heartbroken that Air no longer expressed feelings for her as she once did. Longing for comfort, she decided to visit Loft in Cha-Am, bringing along the pair of ceramic cups she had just finished crafting. That meeting drew them closer together, and for a fleeting moment, Pure found herself forgetting the sorrow of missing Air.

Pure and Loft's relationship begins to grow deeper, while Air starts to sense a change in Pure after returning from France. Determined to settle things quickly, Air tries to clarify her own relationship with Lamp. Meanwhile, Loft visits Pure more frequently, and the two gradually become closer-far beyond the bond of mere acquaintances or siblings.

Air decided on getting a divorce from Lamp and explained it to Juthamas, but Juthamas refused to accept it. Air then went back to Pure, asking her to wait because she was about to finalize the divorce. Pure, however, began to hesitate, unsure whether the one she truly loved was Air or Loft.

When Loft discovered that her brother Lamp was about to divorce Air, her heart sank, for she knew her own fleeting moments with Pure were about to end. With tears in her eyes, she went to bid Pure one final, aching farewell. At the very same time, Air returned to Pure-only to find that the love once shared between them had already faded. Crushed and trembling, Air urged Pure to bare her heart to the man she truly cared for, even as her own world was crumbling for being too late to reclaim the love she had lost.