Alienoid

Guard and Thunder have served prisoners from outer space in the human body. They found a girl during a mission and raised her alone. In 2022, an alien spaceship arrives in Seoul's sky, and Detective Moon witnesses something weird. The twist is that he is not the only one who saw what he saw. Meanwhile, 630 years ago, in the Goryeo dynasty, a young mage named Mureuk seeks a magical sword with a lot of bounty money. His mission gets deterred when a young lady with thunder interrupts him to get the sword. The blade is hunted by the two and other mysterious and magical figures. What is the sword, and what power can it yield?