There's no attempt, nor real need, to explain the back story - at this point, the Potter franchise is not one for casual fans, and it's a safe assumption that anyone watching the grand finale knows what went before.
Harry (an increasingly confident Daniel Radcliffe) and school pals Ron (Rupert Grint) and Hermione (Emma Watson) continue on their quest to destroy Lord Voldemort's remaining Horcruxes, which ensure his invulnerability.
Learning of their plan, Voldemort launches his final attack, leading to the ultimate showdown with Harry that the entire series has been building up to.
The special effects work well without being overdone and distracting from the humanity of the story, while the 3D graphics add plenty of value, and the climactic scenes are handled well.
The film's only real failing is in the once-over-lightly treatment given to some of the scenes cherished by the more hard-core Potter fans.
However, it's a minor quibble at best - splitting the final book into two films is surely evidence enough of the film-makers' efforts to keep as much of the Potter story intact as possible.
And so, a film series much loved by adults and children alike comes to an end - when the credits do finally roll, there's a satisfying sense of finality but it's tinged with just a bit of sadness.