It gives background on how she and Lucian met. And someone was helpful enough to give us a minor English summary.
At the end it says Lucian shatters Thresh's lantern. Senna is free, but she doesn't pass on like Lucian wanted. She's corrupted, but she's in control of it.
Lucian is unable to be happy about this, he loves Senna, but she's consumed by the thing he hates most and he can't bring himself to trust the situation. And he refused to believe Thresh is really gone.