For the teaser Dax says none of her hosts were any good with music, but then she plays a song on Jake’s keyboard. So she’s modest, that’s not much of a teaser

Dax and Sisko play old 2D chess, but Dax accuses Sisko of cheating and knocks over all the pieces.

Then Dax starts having visions

Sisko and Bashir take Dax to the Trill home world. I think they could’ve just used a runabout rather than put a whole crew to work operating the Defiant

They go see a “guardian” who knows everything about symbionts. He’s a little off

They look up the guy who wrote the song Dax knew, and it makes her go into shock

With some more investigating, and the help of this old man, Sisko and Bashir figure out that Dax was joined with a murderer

They confront a lady in charge. She tried to keep that host a secret because it reveals that about half of Trills are able to join with a symbiont, not the 1 in 1,000 figure they tell people.

Dax goes in some water and accepts that the murderer is a part of her