It is a novel about the family and romantic relationships of two siblings, both queer and of mixed Russian and Māori descent, and set in Auckland.
Reviewer Hannah Tunnicliffe for Stuff said Reilly "fuses socio-political commentary with humour, making Greta & Valdin both smart and funny.
[8] Rachel O'Connor for Landfall noted a level of "information overload" but concluded "there is much to enjoy in Greta & Valdin, and hopefully much more to come from its author, whose youthful, funny voice delivers a fresh and entertaining tour of life and love in Auckland's CBD".
[17] In September 2022 Reilly was a judge, together with Harry Ricketts, of the Nine to Noon short story competition on Radio New Zealand.
A review by The New York Times described it as a "generous, tender debut novel of family and self-acceptance" and "so brimming with life it can feel almost dizzying".