If You Take My Bones, Why Don't You Make a Mistake If I Take My Body?

A class of people travel through time (there is a chat group), and the protagonist, his ex-girlfriend and his love rival are reincarnated into a family's genius. The protagonist is pregnant with the Supreme Bone, which is captured by his love rival (the reincarnated protagonist's younger brother, Huai Zhongtong) and his stepmother. (The ancestor of the family doesn't care, but the classmates don't help). But in fact, the protagonist: Jie Jie Jie...