Is it the Pickled Herring Tavern? If so
<span class='standouttext'>Spoiler : </span><span class='spoiler'>talk to all in the tavern, get the key from Mr Pickle - go up search all rooms and click on the locked one - then descend and approach the unfriendly guests (go very near). They will fight you - then talk to Moreena gain. She will give you a key to her room => chest. </span>
Please highlight to read - if you're in this tavern. If not, please, give more details.
