Art by Lynn Phillips Nelson
We all know the first line of a query is your "hook." I call the last line the "sinker." You want it to punch them in the face, in a nice, friendly kind of way that makes them unable to forget you after having read the 300 other queries in their inbox.
Also, for my brave Saturday Slash volunteers I will gladly do follow-up slashes (each more kindly than the next) on your query if you post them on the Query Critique board over on AgentQuery Connect. You'll get advice from me, and also people who are smarter than me. If you do post on AQ, be sure to follow the guidelines and let me know you posted so that I can follow up!
And now for the next brave volunteer. For clarity, my comments are in yellow.
When Anna Wilson not sure last name is necessary, not a big deal at all, just a rhythm thing. took on the daunting task of restoring Matt to a state of sobriety a
Before falling to the floor passed out drunk, Matt Hayes declares his love for Anna. Wishing she could tell him she loves him back, she just can’t do it. Instead, she decides to search for someone who can. This paragraph here is telling exactly what the next para is showing. You can strike the whole thing, and find somewhere to insert the idea that Matt is in love with Anna, but it's not returned, elsewhere.
When she discovers a journal that Matt’s father Tom had kept, she believes she has found a way to save Matt from his downward spiral of depression. Despite the fact that everyone believes Tom is dead, this journal gives her reason to believe otherwise. Do some rephrasing here to get all your ideas together into more cohesion. Matt' loves Anna - Matt is depressed - Tom should be dead - Anna thinks he's not - Anna thinks Tom could be the key to saving Matt. That's the order you should address the issues in. You've got everything here but the logical order is mishmashed. Embarking on a search through shark infested waters, strike the comma to a hellish island in the middle of nowhere, she discovers that the man she is looking for is indeed alive.
However, a wrench is thrown into her plans when she finds herself falling for Tom. Now the man who is supposed to be Matt’s saviour, strike the comma could be the man who ends up bringing him more pain and heartbreak.
When she discovers that Tom isn’t Matt’s real father, she only finds herself lost in more confusion. Sure this would make it more acceptable for her to feel the way she feels about him, but if she is even going to consider pursuing the flutterings of love that are developing between them, she has to find a way out of the spotlight of Matt’s desires. Again, you've got two paras that are doing the same work for you. The good news is that you've got a great sinker -- on the end of the para above this one :) The only new information we have her is that Tom isn't Matt's biological father, and that's not really necessary query info.
There are two paras that can be stricken entirely and you're not losing anything within the query - and that's a good thing! Get the middle para hammered out so that it's falling in a logical order and you'll be in much better shape.
Also there are a couple of cliches here that aren't necessarily horrible things that are going to sink you, but consider finding better phrasing than "downward spiral of depression" and "a wrench thrown into her plans." They aren't horrible writing sins, but your query needs to shine with originality, so see if you can do some inventive rephrasing.
On the whole it sounds like a tear-jerker! Polish up your query, I bet you get some bites!