Here is the plot of the first novella, Every Heart A Doorway, from Wikipedia:
The story is set in a boarding school for teenagers who have passed through "doorways" into fantasy worlds only to be evicted back into the real world. It serves as something of a recovery center for boarders who find they no longer fit in, either in the "real" world or their own uncomprehending families. For a fortunate few it is just a way station until they can find their ways back to the worlds they do fit into; for others, it's the least bleak choice in what may be a life-long exile. This unhappy ending for the students takes a terrifying turn when some of their number start turning up dead. A small group joins together in an attempt to expose the person committing these murders before it is too late to save the school, or even themselves.
Through twitter, the author announced the news of her four-novella series being adapted and that she won't be involved with the screenplay or production, but believe the material is in good hands. At the moment the project is at a very early stage of development so keep an eye for more update about Wayward Children TV adaptation.
source material: https://screenrant.com