"Τι είχε γίνει;"
Translation:What had happened?
Hm, I guess it could, but here on Duo, these cases are almost always specified by Αυτός, αυτή etc. Even if the pronouns are not really necessary in spoken Greek. ^.^
Also, a tip: If you wanted to ask what happened of a specific person, you'd say "Τι απέγινε (αυτή/αυτός);"