Going by memory but I think the seme's family are wolves or foxes or tigers or something. He thinks he meets his fated pair but it was a trick by his real fated pair (who is angry the seme doesn't love him) who teams up with his half-blood brother to genetically engineer someone else to be his fake fated pair. There is some sort of family blood curse which is why the seme needs to be with his fated pair or he needs his fated pair to become the next head of the clan. The half-blood brother falls in love with the uke and botches a fake rescue attempt. The uke gets sold off at slave auction but it turns out he might be from a rare bird clan. There's also some romeo & Juliet style stuff with poison and sleeping pills. I also think the uke is from our world but the animal stuff is a secret world.
The ending has been so rushed and I can't believe they just glossed over adult Yuna. Did this get cancelled or something?