I think they're asking about a blurb, and not a query, since they don't ever mention an agent. However, they also don't mention self-publishing. My guess is that they "think" they're supposed to be writing a blurb, when in reality they should be looking into researching queries.
Regardless, my answer doesn't really change. Both the blurb, and the query, should not do what I think you're doing: dig too far past the beginning of the novel. More importantly, if the "juicy" stuff doesn't happen until deep within your novel, where you can't write an interesting blurb that doesn't include it, then you should consider reexamining your story structure.
The strange exception to this is in queries, when you reach that last paragraph that sets up the "choice" that closes and hooks the agent into asking for fulls.
Your blurb, and even the bulk of your query, should focus largely on the beginning of your story. For instance, let's look at Hunger Games blurb:
In the ruins of a place once known as North America lies the nation of Panem, a shining Capitol surrounded by twelve outlying districts. Long ago the districts waged war on the Capitol and were defeated. As part of the surrender terms, each district agreed to send one boy and one girl to appear in an annual televised event called, "The Hunger Games," a fight to the death on live TV. Sixteen-year-old Katniss Everdeen, who lives alone with her mother and younger sister, regards it as a death sentence when she is forced to represent her district in the Games. The terrain, rules, and level of audience participation may change but one thing is constant: kill or be killed.
That entire blurb is basically the first chapter of the book. (That doesn't work as a query, though, and disobeys many query rules haha.)