Sommar Serrano is a young, adventurous and obedient heiress of the Serrano household. Laking Maynila man ay hindi pa rin mawawala ang pagmamahal niya sa probinsya ng Bulacan. Maagang namulat sa responsibilidad na siyang pinilit niyang mahalin dahil sa pamilyang kanyang kinabibilangan. The most caged ones were the wildest among others because the more you grip it tighter, the more it wants to be freed. Ganyan ang sitwasyon na pinaglalagyan ng katulad ni Sommar kaya naman hindi siya nauubusan ng paraan upang kumalas sa lahat ng pagkakataon na nagigipit siya ng kanyang pamilya. Her will to be freed keeps getting stronger. An heiress who always runs. But this time, she chose to run towards the fields and enter a dark, creepy and lifeless castle-like mansion. There she met the man that everyone talks about named after a harsh and barbaric word, Cruel. Armored with a barbarous demeanor, arrogance and a fair of mysterious aura of a wicked prince without even trying, he stands in the middle of the empty and lifeless ballroom dance floor. She then thought he lived by his name, Cruel. He's harsh unlike those boys who please and treat her as a princess at school. Dull, cold and lonely but Sommar takes it all to be his friend. However, Cruel knows better behind her facade and mask, lies a pretentious lady. But both of their lips were sealed with lies and secrets so how can her stay in Sta. Lucia make a difference? Will Sommar get the freedom she wanted all along? Or beautifully crush Cruel's life? Nevertheless, she's not just a simple summer after all, she is a cruel one.