If I wanted to summarize Naruto, I would have to summarize the ideas. You don't want to give out specifics like who dies, any identity reveals, or for that matter just about anything revealed in Shippuden.
"Naruto is a boy who, on the day he was born, coincidentally had a giant demon fox spirit attack his village. Using a special kind of energy called chakra, a powerful individual sealed this demon fox inside of Naruto to protect the village. Naruto's parents however die in this attack, and he resorts to troublemaking for attention, as well as aspires to become the Hokage, the leader of the village, for people to acknowledge him. To do so, he must become a great ninja, someone who uses their chakra to perform special techniques, such as manipulating the elements to spit fireballs, raise walls of rock, blow gusts of wind that can slice through trees, manipulate the body, or create illusions and trick the opponent. The story of Naruto is about how he grows from a 12 year old low class weak ninja with his friends/classmates and their teachers, including his training to become stronger, personal struggles as well as the ones with the other villages, and fights with strong opponents. It also has his internal conflict with the demon inside of him as well as his attempts to be acknowledged by people as he grows in strength. It constantly has you wondering how things are going to turn out as strategy in combat is critical as they often fight enemies more powerful than they are, and must come up with the strategy to get ahead. Most people find themselves rooting for Naruto as they watch him do what seems impossible as due to his life as an orphan, as well has his overall complete lack of talent in all but a few specific things, has made him vow to NEVER give up, ever, and allows him to see the truth behind his opponents. Death is there for all sides, but it is not always the only solution because of Naruto."
The idea of that kind of summary is to bring up every important idea without saying what actually happens. It's important to mention death in some way, as well as his lack of talent and how he is still able to become strong, but that his power is not his ultimate strength, in Naruto, the world is a bad place, full of wrong, and he is trying to change that in a way no one else ever could.
If it is interesting enough to consider watching a few episodes, then, unfortunately, the best summary of the entire series up until the war is the entire ordeal with Zabuza, the first real opponent they fight. It's probably quite a few episodes in, as it has been a long time since I was back there, but it really summarizes everything until the war in Shippuden. If they liked the Zabuza arc, they will most likely like everything up to at least the war, where things change a lot, because it's a war, and also really far into the series.