A title, Duh?

The day started cheerfully, without any gloom, like a meadow filled with lovely flowers, with the blue sky. Blue and her dog, Red, Violet and I was going to villa of Blue for our summer vacation. The country house was located in a quiet forest that had trees with deep green foliage and large, tall trunks. When we arrived the lodge it was cleaned and had two bedrooms with bathrooms, a terrace and other well-cleaned rooms. after we had dinner and hanged out, and then fell asleep. But we never knew, that we had to run away. In the middle of the deep night, "Ahhhhhhh!!" Blue and I woke up, by the sharp scream of Violet. And when we arrived to the scene the cold corpse of Red and Violet shivering in terror in the bathroom came in to our vision. We first calmed down Violet and asked her what happened. "R..Red was killed by a monster with tentacles... The monster had sucked all her blood with that...!! And when I tried to run away and turned my body, I saw the shadow... and it had changed it's shape to a human... Then it disappeared, and I shrieked and you guys came.." Violet revealed the situation carefully, and this story appalled all of us. Deep silence made by the melancholy filled the room, after this tragedy. After the temporary silence, I carefully opened my mouth. "That mean... that there is a murderer in this house....?" "I... think so... Wait, we need to get out of here! Let's get out of this horrible place and call the Police!!" Blue said shivering. "....The door doesn't open....!!" Violet shouted holding the locked doorknob. It meant we were occupied and isolated completely. Also we called the police, but the answer was that they would come in 30 minutes. "Oh no... guys. But we have to get out and survive..!!" I said slowly, shivering a lot. "Let's look for some items for safety. I'll see The kitchen and the living room. Yellow, you go to the first bedroom, Violet, you go to the second bedroom. And 10 minutes later, come to the terrace." "Okay." "Bye, see you soon...!!" 10 minutes later we couldn't find any survival items, and any other people. However we founded Blue's dog dead coldly, so we started to panic. "There was no one, but the dog was..dead.." "...That means.. the murderer is in us...??" "...I think so.. " Now we couldn't depend on each other, but suspecting. "...Blue. Just tell the truth." Violet spoke quietly, but furious. "You had made us come here to kill us, and murdered red by the ability of sucking blood!" "Wait... Also you made us to look and be alone! You were the one!!" Blue walked backwards and talked. "No...! It's not....!!" "...!!" Blue fell from the terrace that was the 3rd floor, and its neck was totally broken, but there was no tentacle which was the sign of the traitor in her dead body. "What...?" I turned my body and saw Violet, smiling. The tentacles came out and started clutch my body and suck my blood. Consciousness started to disappear, and heard the last sentence of Violet. "Bye, see you soon." ....