"You" have been given a choice of lucky numbers, each of which sends you on a different adventure at Poison Lake. Swimming in the lake is dangerous, but you may not be allowed to stay out of the water, and the consequences of doing so vary with each path.
Weekend at Poison Lake provides examples of:
- Adults Are Useless: This is averted in three of the storylines in this book. One path in Storyline B (the ice cream hungry aliens) has you receiving help from Ben and JoJo, the ice cream manufacturers, when you explain what's happening because you're not the first person the aliens have messed with. In one of the endings for Storyline C (the stolen jewels), your character is saved from the Bittermans by the old woman screaming "Fire!" This causes the townspeople to gather at the lake, where they see you being attacked and rescue you. In one of the good endings for Story D (the Moss-man story) you telling your parents that you're being stalked leads to them calling the police and having the man arrested.
- Big Damn Heroes: The old woman in the third story manages to save your life by screaming "Fire" and drawing attention to the Bittermans trying to drown you once people have gathered around her.
- Bigfoot, Sasquatch, and Yeti: The first storyline have a scenario where you encounter a sasquatch who pursues you relentlessly.
- Bittersweet Ending: This book has one where you're stalked by a mysterious man trying to drag you into the titular lake. He does... and then you find out that you're one of a species that live at the bottom of the lake, who gave you to humans to raise. You're sad to leave your human parents but happy to finally be where you belong.
- Bland-Name Product: Ben and JoJo Ice Cream? Nope, NOT a knockoff of Ben And Jerry's ice cream. Not at all.
- Covers Always Lie: Approximately NONE of the storyline features the blue, amphibian monster seen on the front cover. It's very likely a reference to the ending where you discover your lineage to be a fishman, but then you're going into the lake, and not out of, like what the cover shows.
- Cursed with Awesome: In one ending, you're forced to eat chocolate cake every day to keep a terrible smell from coming back.
- Good Feels Good: In this book, when you help the old woman recover her missing jewels, you feel good knowing you were able to help her even if you don't get a reward. But then you do get a reward from the old woman, along with the town renaming the lake after you for proving it's not poisonous.
- Hilariously Abusive Childhood: In one scenario of this book, your parents hire a guy to dress up as a lake monster to scare you (he even goes so far as to try to drown your dog in front of you.) It's played for laughs.
- I Don't Like the Sound of That Place: This book has a double example — there's the titular lake, but you're also living in a house called "Vampire Lodge."
- Knight of Cerebus: After the first two plotlines are largely comedic, the Bittermans in the third storyline and the Moss-Man are in the fourth storyline are much more intimidating and dangerous and make their plots more serious. The Moss-Man stands out as a mysterious Humanoid Abomination that stalks the reader character, while the Bittermans are greedy jewel thieves willing to poison and outright murder a child.
- Luck-Based Mission: This book is this, literally. You pick between four short adventures based on Poison Lake, which each come with their own designated lucky number between two to five, and you decide how (or if) to use your lucky number during any perilous moment. Interesting concept, but the problem is that there was no logical way to deduct when to appropriately use your luck, as it could backfire at anytime. Yeah ... there's a reason this book wasn't well regarded.
- Meaningful Name: The Bittermans are a pair of greedy jewel thieves willing to poison and even drown an innocent kid to get their hands on stolen loot.
- Plant Person: The Moss-Man of the fourth story looks like a waterlogged corpse with moss growing on his body.
- Random Events Plot: This book doesn't even hide that it's this trope, since the trope IS part of the book's premise. The book has four varying storylines, which are equally weird and random.
- Tampering with Food and Drink: In the third storyline, the Bittermans trick you into thinking the lake really is poison after you start vomiting and collapse. When you wake up, you conveniently overhear the two discussing how they mixed a rotten egg into the chocolate milk left with the lunch your parents put out for you while you were swimming.
- This Is Gonna Suck: The second storyline involving aliens have this happening to you in more than one bad ending, where you chose to use your lucky number only to have the outcome screw you over. For instance, having three times the bad luck resulting in three alien saucers surrounding you instead of just one.
- This Loser Is You: One ending has you try to tell your parents about the Bittermans' plot, so your parents take you home to safety and you don't get to enjoy your vacation or find the jewels. The book insults you, saying you should have expected a boring ending from trying to get an adult involved.
