Tom was sitting in the library of Riddle Manor when he felt someone enter the wards. He recognises it as Lilith, Draco and Lucius. Severus was out for the day, collecting supplies for his potions lab.
He notices the magical power in the manor change, but brushes it off. All of a sudden he hears a loud scream coming from downstairs and was almost taken aback from a sudden surge of magic radiating throughout the manor. He throws his book down and apparates downstairs, worried that scream came from his grand-daughter.
When he appeared in the living area, he was shocked to see his worry was correct. Lilith was on the floor, head hanging and panting heavily. Draco was by her side, as always, his hand placed on her back and a very worried, almost scared, look on his face. Looking at Lucius, Tom sees him have a very different look on his face, a quite curious one. From this he can definitely tell that the scream came from Lilith. But what of the magic surge, it wasn't yet clear.
Tom decides it's best not to invade Lilith's space with Draco and starts to slowly walk over to Lucius, still keeping an eye on the kids.
"Lucius, what happened when you were out?".
Lucius sighs, "We had another run in with...". He looks over at Lilith and decides to be more careful with his words to not accelerate the situation, "...them, and you know how she feels about them. Their confrontation made her very upset and then...".
He gestures towards her, to which Tom nods. He cautiously starts walking towards Lilith and Draco, worried for his grand-daughter. He knew they must have said something bad to get her this upset.
"Lilith? Sweetheart?".
Lilith slowly looks up at Tom, still panting heavily. The look in her eyes when she made eye contact with her grandfather was full of fear. Tom leans down and sits on his knees in front of her, nodding to Draco. He slowly lets go of Lilith and allows her to fall onto Tom, her body physically exhausted.
As soon as he wraps his arms around her, he immediately could tell where that sudden surge of magic came from. He needs Severus to come home. He turns to Lucius to see him holding his son, who is very worried and scared.
"Lucius? Would you at all be able to send a Patronus to Severus?".
Lucius nods and carefully grabs his wand from the cane, making sure to keep his other arm around Draco. He sends the Patronus out to let Severus know that Lilith needs his back home instantly.
Tom thanks him and looks down at his grand-daughter in his arms. She appeared to be slowly falling asleep.
He starts slowly petting her head, "It's alright, sweetheart. I'm here. Your father's on his way now. I'm sure he's racing home as we speak".
Speaking of the devil, Severus apparates into the room, immediately running to his father and daughter. Tom slowly puts Lilith into Severus' arms.
Lilith stirs and whispers, "Daddy?".
Severus wraps his arms around her, "Shh, I'm here, baby. I'm here".
She snuggles into him, "M'tired, daddy".
Tom rubs her head, "Go to sleep, sweetheart. We'll be right here when you wake up".
"Draco?".
Tom smiles, "He's here, don't worry".
Lilith cuddles further into her father and falls asleep.
Severus looked up, "Father? What happened?".
Tom sighs, "I think Lucius is the better person to ask".
Severus turns to Lucius, who moved to sit on the couch with Draco leaning into his side. Lucius sighs and gives a small summary of the events that led up to this. Severus and Tom lock eyes and nod, knowing they are going to have a chat about this later.
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~ Author's Note ~
How have I just now realised that you guys don't really know what Lilith looks like? Here's an avatar I created so you have an idea (it's when she's a bit older but you get the idea):