The day that Lucy's life turned upside down, began like any other ordinary day.
Natsu was fighting grey, Ezra was eating a strawberry cake and Happy was eating fish while offering some of it to Carla.

Lucy decided that she deserved a break, so she went home alone that day. Unfortunately she forgot something very important, she forgot to close the door.
Meanwhile, a very dangerous mage was running loose in Magnoria, seeking shelter. Luckily for him, he found it. An open door awaited him. An open door leading to Lucy's apartment.

The mage tried to snuck in as quietly as possible, however his gasping breath, caused by all the running, did not go unnoticed.
Lucy, alarmed by the unplaced, sudden noise in her cozy, little room, dropped her pen for she had been writing a story and went to check it out, her keys safely on her belt.

You can imagine her surprise when she came face to face with a notorious mage in her apartment. The mage however, reacted faster than Lucy did, using the advantage of surprise.

He put his hand on her mouth, thereby avoiding any sound that Lucy might have made. He reacted quickly when he saw her hands moving towards her belt, in search of her magic companions.

He smiled when he threw her on the ground and sensed her magic power, smirking over the fact that this little, now vulnerable girl had quite some. With a now even more wicked smile, he began to drain her magic, with highly advanced, forbidden magic. With his new magic powers, he felt he could use a transportation spell once again, for he had emptied his own resources. With this, he disappeared along with the girl, leaving only a set of magical keys and an unfinished story, about a certain fire-breathing mage behind.

When Natsu came to Lucy's apartment later that night, he found it strange that the door was unlocked. Suddenly feeling odd, he took a whiff and smelled the strange odor of an unknown male.
He quickly barged in, calling out Lucy's name, feeling an odd fire burning in his heart, which obviously others could identify as jealousy. Being Natsu however, he was too inexperienced to identify this certain uneasy feeling.
He rushed into all the rooms only to find each and every one empty. Not knowing where to look next he sat down on a chair, holding his head in his hands in pure frustration.
His eyes then caught something lying on the desk. A book was still lying open, a feather pen still slightly wet and an unfinished sentence in the middle of the page.

This was very, very weird, for Lucy always tried to hide her stories in embarrassment and thus never left them lying in the open for them to find.
Without him even noticing, he started reading the words written down in Lucy's handwriting on the paper.

'(..) It really was a dangerous mission and I don't think I could have made it without Natsu. Lately I have been noticing that I depend on him more and more. And when I think about him, his laughter, his eyes or the sound of his voice, something just flutters inside my stomach. I really like my teammate and I don't know if this feeling is good or bad. You know, I think I even L-'

The words just stopped.
Natsu just kept reading them over and over for some time, making sure he grasped the aspect of every word. He then felt a blush rushing over his cheeks, suddenly feeling the urge of letting out his fire, without holding himself back.

He kept thinking about the last words Lucy had written. What could that 'L' mean? Learn? Like? Or maybe even Love?
With that thought, his whole head turned bright red and he began to pace around the room, when his foot suddenly hit something.

Seeing what was lying on the ground, he knew something was very, very wrong.

He almost flew out of the room, fire unconsciously burning on his hands.

Because when would a celestial mage leave her keys behind other than when forced too?