Dipper and Mabel are both juniors at Gravity Falls high school. On the first day Dipper gets a new history teacher. This is BillDip.

In 10 grade bill seeks out dipper with a dilemma that will either ruin dippers life forever or change it for the better

It's been 4 years since twin siblings Dipper and Mabel visited Gravity falls for the first time and they are returning for the summer once more. Although Mabel is incredibly excited to see their Grunkles, Stan and Ford, Dipper is troubled by other teenage dilemmas and feels more alone than ever. He has nobody to turn to, that is, until he rediscovers the delights of Bill Cipher.