The group were hired by Gundrun Rockseeker and Sybill Trammall to take some supplies to Phandalin with some further instructions on where to take them next. However, you were sieged by some goblins and you managed to persuade Klaarg, the branch manager of this gang of goblins to allow Sybill to go free in exchange for carrying out some delicate disciplinary action by bopping on the head some upstart goblins in the company.
Upon reaching Phandalin, you speak with Sybil - a mage from the College of Silverymoon - who has advised she has been foretold that the wands of the Seven Sisters are buried deep within a mine that Gundrun Rockseeker had. However, you need to seek out the Black Spider to find the dwarf and the map first.
On your way to The Black Spider, you are approached by a druid Aurora to collect items for a potion which you agree to do. Upon finding the Black Spider, you find his name is Frazer Rockseeker and is the half brother to Gundrun; jealous of the riches Gundrun has and how he has been abandoned by everyone for being a half spider half dwarf abomination, he asks the group to choose. You decide to allow Frazer to kill Gundrun and become the rightful heir to the Rockseeker company and he asks you to find somewhere for him and his spiders to live in peace.
On the way to Wave Echo Cave, you stay in a small village called Kindleguard at Mrs Lovett's Inn and Pie Shop. You are almost fed to a giant plant before escaping. Which, yanno, you barely survived because those villagers are BEEFY.
At Wave Echo Cave, you fight your way through to find that the wands were not there but a mysterious hooded figure is - apologising. She needed out of that vault and leaves as soon as she could. You are all significantly better off as you get the gold.
Sybill - disraught that the wands she had been dreaming of for decades was a bunch of lies - decides to join the party.