Disclaimer: Everything you know belongs to the genius that is J.K.Rowling.
A/N: Very weird, but still!

Hogwarts
20th of August, 1974.

Lily walked over to the giant statue. Sniff sniff. She could not exactly tell whom the statue was supposed to be, but there hadn't been anyone touching it for quite some time. There was some type of magic over it, she sensed. Much like the portrait of the fat lady... She turned back into her human self, having walked around in the castle on four, fur clad cat paws for some time now.
"Daaaaaahls! Viiiiiiiiii!" A cremetabby and a black cat came running down the hall. The creme one turned into a panting Dahlia who demanded to know what Lily had found.
"Do you think this statue of," Lily looked at the statue, now in normal size, "Rowena Ravenclaw is an entrance to something?" The black sniffed at the statue and turned into Violet.
"It's clearly something magic about it." Lily nodded.
"Yeah. I sensed that."
"How can we get in? It's not the Ravenclaw entrance is it?"
"Nah... That one is further down ... I think." They looked at the statue. It figured a pretty woman they recognised from one of the paintings of the founders they had seen in the Astronomy Tower. Lily studied her pace when the statue suddenly blinked. She pulled her hand back.
"What...?" All three took a step back.
"Don't worry girls. I'm only a statue, I can't harm you, and I don't want to harm you." They still looked sceptically at the statue.
"I'm a very magical object. Only accessible to the Heirs of Ravenclaw, and only female heirs that is."
"But... but... We're not the heirs of Ravenclaw..." Dahlia said.
"Oh yes you are. I can sense that. I am the entrance to a part of the castle no one has entered since 1944 when Rose left Hogwarts."
"Rose? Rose Myers?"
"Yes! That's the one. A lovely girl she was. An idiot of a man made her pregnant in her fifth-sixth year. I guess that you are her grandchildren?"
"No, daughters actually. We were magically kept away from this world for 16 years." Violet said.
"Oh... I see. Maybe you want to enter your mother secret cave as she called it?"
"Oh yes. We would very much like it."
"Well, what would your password be?"
"Paloma. It's Spanish for pigeon. Is that alright with you?" Lily asked her sisters. They nodded.
"Well that Paloma it is for now." The statue said and jumped aside. The three girls carefully entered the opening. A little entrance room showed itself. Here were wardrobes to hang up your clothes and put aside your shoes. The colours where the Ravenclaw blue and bronze. On their left there was a door which led way to a small bathroom with only a toilet and a sink with a mirror above. Right in front there were two huge doors, which were amazingly easy to open. They stopped, amazed by what appeared in front of them. A huge living room with several soft sofas and chairs. A soft wall-to-wall carpet and beanbags scattered all over the place. Huge windows with light curtains and a fireplace to sit in front of in the long winter months. Paintings of Rowena and wonderful landscapes hang on the walls, plants and flowers made the atmosphere more homely. They opened door by door. They found several bedrooms with bathrooms. And those bathrooms were nothing like the one in the hall. They were huge. They included a shower, a normal bathtub, a bubblebath, a toilet, a sink, some closets filled with fluffy towels and stuff... They bedrooms contained a huge double bed, so soft you hardly can imagine, a huge wardrobe including some clothes. The girls were awed. Three bedrooms with one bathroom each connected with doors laid next to the living room on the right side. On the left they found a small kitchen (so you didn't have to go down to the kitchen all the time), a library with desks for studying and the best: A huge bathroom, much like the prefects bathrooms, with several swimming pools and bubble baths. There were diving boards and slides too. They also found a stair that led up to another eight bedrooms or more, there were even some unfurnished rooms. After looking around they seated themselves in one of the huge, soft sofas in the living room.
"Girls?" They looked up at a painting of Rowena.
"Yes."
"You can open the painting of yourselves out in the hall, that will lead to a hall with several magic doors. There are signs on the doors that will lead you to several places around in the castle. The magic also does that only people you want or trust to enter will be able to enter through them. Some leads to the Gryffindore rooms, the Hufflepuff rooms, the Ravenclaw rooms the Slytherin rooms, an other to the kitchen, to the Headmasters office, to different halls around in the Castle and so on."
"But there are no painting of us in the hall." Violet said.
"Oh yes there are. In your mothers time there were a painting of her."
"Well, thanks."
"You're welcome." She smiled at them and left the picture. Curios the girls left the living room and entered the entrance. And truly, on the left side there hang a huge painting of themselves. Dahlia looked at Violet next to her.
"But how do we open it?" Violet shrugged.
"Maybe we should just make up a password..."
"Rose." Lily said and the painting swinged open.
"What... How?"
"I just searched inside of myself. It's a painting of ourselves after all."

After studying the doors and signs for a bit they decided to visit the Headmaster who said he would be present this week, they had mostly been left to themselves with only the caretaker Hagrid outside, and ask if they could move to 'their new-found cave'. Dubmledore gave them permission to do so and they brought their belongings from their 5th year dorm and moved into the 'Rowena-cave'.