Souma Tendou, who spends his days in idle monotony, has two "favorites." His online favorite is Henrietta, a hugely popular VTuber. His real-life favorite is Hiyori Yatsumi, an idol and voice actress. Souma was supposed to be spending his university life supporting these two idols... But then, one of his favorites unexpectedly moves into the room next door!? Excited by this dream-like turn of events, Soma is thrilled, but what he discovers is the disappointing true nature of his favorite...
After his life on Earth comes to an end, Lynos is reborn equipped with a rare and powerful guardian magic that only a few select individuals, known as Barrier Masters, possess. Unfortunately, his fortunes take a turn for the worse as he is reincarnated as a vulnerable child who is slated to be sold into slavery. However, Lynos manages to narrowly evade his ill fate and is taken in as a servant by a wealthy noble clan. With their guidance, Lynos is trained to become the protector of the family's most important members. As he overcomes obstacle after obstacle, Lynos prepares himself for a future full of adventure and exploration as a skilled Barrier Master!