My players have successfully beaten the kobolds in the local mine!
They decided to try a frontal assault on the mine, despite the difficult approach 100 ft. in every direction (reskinned barbed wire trap from the Pathfinder SRD) meaning they couldn't close to melee. The samurai had sold his shortbow last session too, so I had a good laugh at his expense when he realised the dozen javelins he'd picked up would be useless. The gnome telekineticist used their simple blast to knock down the kobold's watchtower, and from there they fell to ranged attacks.
They were smart enough to search the door and find the two traps on it, making good use of a 10 ft. pole to set them off. Inside the mine they found a passage coated in lantern oil, on the other end of which was a kobold who threw a smokestick to give himself concealment. They set fire to the oil themselves, but took a pair of acid flasks worth of splash damage from the kobold on the other end of the passage while they waited for the two rounds of burning oil to go out. Then the gnome charges into the passage once the oil is gone, only to set off two fire trap runes placed by the unseen kobold sorcerer inside the room that were underneath the oil. The samurai sets off a third before deciding it's worth actually checking for traps, whereupon they find the remaining two runes and safely move around them. Once they close to melee with the kobold rogue and sorcerer, it's over fairly quickly.
They interrogate the sorcerer after capturing her alive, learning the leader's name, that the kobold leader is transforming into a dragon, and that they have a pet dragon too. They release the kobold prisoner and move further forward, failing to search for traps as they move inside the next room. Lucky for them it's not a trap, but there are four kobold barbarians hiding under camouflage netting who get a surprise round on them. They get some solid hits in but don't manage to deal serious damage, but after healing the group decide they're spent for the day and retreat to rest.
The night passes as they keep watch on the mine entrance, seeing a kobold peek out but immediately retreat. The next morning they attack again, finding a thirty foot deep, five foot wide chasm running across the room. A pair of kobolds riding dire war weasels shoot from the back of their mounts with shortbows, jumping across the chasm to avoid being caught in melee. One of the kobolds goes down, his companion succeeds on a handle animal to get the riderless weasel to attack the samurai, and the weasel rolls a natural 20 and crits! Per the monster entry, it latches on with its teeth, so the samurai gets a feral weasel hanging off his family jewels. Luckily he manages to (carefully) strike it with his sword, killing it and avoiding taking strength and constitution damage the next round. The second rider is quickly cut down shortly afterwards.
Finally the group descend down a 60 ft. shaft, and reaching the bottom find the boss chamber lit by six burning braziers. The kobold boss is described as shimmering with a heat haze and dripping liquid flames from their clawed fingers, and it delays long enough to allow everyone to enter the room before pressing a switch on its throne, triggering the collapse of the ladder leading up the shaft and causing the braziers to start emitting concealing smoke in a 20 ft. radius burst. The party have an 'oh, shit' moment when they realise that they've completely forgotten to use the wand of resist energy given to them earlier.
A merry chase ensues as the boss uses the smoke to their advantage, setting the group on fire and burning down their fire resistance with its infusion abilities. The fight ends up being a near TPK when the boss wins an initiative roll with a natural 20 (we roll initiative each round to keep things interesting). The whole party is perfectly aligned for it to hit them all with its 15 ft. cone of fire, and all of them are at single digit health scores.
But wait! One of my players has saved something very special from the very first session of the campaign. At the start of the campaign, each character received a token valid for one immediate action to reroll one d20. They've saved this for over three months, and today they decide they're going to cash it in to make me reroll my initiative. I reroll, and the result is enough to make the boss go at the end of the round.
Snatching victory out of the jaws of defeat, the group emerge victorious, finishing the session exhausted but ecstatic despite the close call. They get a brief description of the massive stone blocking a passage deeper into the mine, painted with pictures of terrified kobolds, a series of draconic words, and a picture of a dragon.
I'm proud of the way this session emerged, and felt that everyone really enjoyed the game. I can tell that the weasel hit will be a running joke for the samurai character for many more sessions to come, and the boss fight was perfectly balanced to be a tough but winnable encounter even without the group remembering to use the clues I gave them to prepare properly. I'm pretty sure they'll decide to skip the optional bonus area in favour of retreating to town and getting their reward (the owner of the mine promised each person their weight in silver for the job). I can tell the group suspect something strange already about the dragon given how illogical it would be for a creature that large to get into a mine, but we'll see if they can figure out the trick or if they'll believe what the kobold told them.