After the talk,Kuro and Miyu go to Miyu's and Illya go to her house.Illya go up to her room then change her clothes,Ruby fly to Illya:
"Illya-san,are you sure you don't want to go to Miyu's place?"
"I don't want Miyu to know that I have the "a" mark"
While they are talking,Shirou standing at the stair:
"Illya!the dinner is ready!"
"Okay!"
Illya look at Ruby:
"We will talk about this later okay?Now i need to go eat dinner"
Ruby just slowly nod and fly away,Illya sigh and go out her room for the dinner.After dinner,Illya go in the bathroom to take a shower.She take off her clothes,she look in the mirror and touch the "a"mark on her neck.She try to remember the omegaverse that Suzuka used to tell her,Illya suddenly remember the Alpha when at the time they get in heat .Illya think it will happen to her in anytime,she stay calm and think that finish shower she must lock up herself in her room and try to control herself.
Few minutes later
Illya go out the bathroom with a new clothes but she still wear the long neck shirt,when she about to go up stair she suddenly pass out and fall down on the ground.Sella hear something,she go out the kitchen and check,then see Illya lying on the floor:
"Illya-san!!"
Shirou sitting on the sofa watching TV,he hear Sella's voice,look at her and see Illya:
"Illya!"
He quickly get off the sofa,run to Illya and carry her up:
"Illya!what wrong!hang in there!"
Sella touch Illya's forehead:
"Illya-san's body is getting hot.Shirou take Illya back to her room,i will go call miss Iris!"
"I understand!"
Shirou go up stair,bring Illya to her room and put her lie down on bed:
"Illya..."
Shirou go out,close the door and go check have Sella call Iris:
"Sella-"
He get knock out by Ruby,fall down on the ground.She pull him,throw him on the sofa,then she fly to Illya room.Ruby slowly open the door,go in,close and lock the door.Illya breathing heavily,holding her chest tight and see Ruby:
"Illya-chan I think you should-"
"The answer is no,Ruby...can let Miyu come here and see me like this...."
"......Illya-"
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"Bakaillya"
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Ruby and Illya realize that voice,they look at the window and see Miyu in her magical girl outfit.Miyu fly slowly in Illya's room,turn her back into normal outfit and stand infront of Illya,but Illya look away while sitting on bed and breathing heavily.Miyu get on bed,sit on Illya's leg and make Illya look at her,which make both of them blushes at each other:
"M-Miyu?what are you doing?" 
"Are you in heat,Illya?"
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To be continued