Planet of Giants starts off as a 'normal' Doctor Who story, with the TARDIS about to make a normal materialisation; then the doors burst open, and there are some frantic moments as Ian and Barbara fight to close the TARDIS doors, but at last they close and they have landed safely as usual, but then the scanner explodes when turned on to see where they have landed.

The TARDIS crew split up to explore, and come across giant versions of Earth insects, with both groups coming to the conclusion that they have landed on Earth, but the incident with the doors has somehow shrunk the TARDIS. This sequence has been written, directed and edited rather cleverly, combining both conversations into one.

A lovely panning shot from the shrunken TARDIS in the paving up to the house reveals the cause of the insect deaths - a new insecticide DN6 which kills indiscrimantly, and Ministry inspector Farrow refuses to approve it; but the main investor in the formula, Forester, murders Farrow. The TARDIS crew discover the body of Farrow, and they prepare to leave for the TARDIS when a cat traps them as its prey...

Planet of Giants works well as an opening episode effectively setting up the mystery and explanation for the size of the TARDIS crew, and providing them with a new conflict to solve - the manufacture of DN6, a task that won't be easy for them. Raymond P. Cusick has once more designed some effective looking sets, both 'normal' sized and TARDIS crew sized sets matching up. Back projection is used effectively to show the shrunken TARDIS crew interacting with proper-sized elements. The incidental music is by Dudly Simpson, whose debut score is very effective in enhancing tension-filled moments.

Dangerous Journey sees the TARDIS crew split up, as Ian and Barbara end up inside the house. Forester and the developer of DN6, Smithers clean up Farrow's body, but it is pretty clear that Smithers is already worried about Forester's actions. Forster comes across as a ruthless businessman, who would do anything to make money; whereas Smithers is a fairly jittery man, who quickly realises that murder is crossing the line in making sure he dream becomes a reality.

Inside, Ian and Barbara find themselves in a laboratory, and they come across some seeds sprayed with DN6, which Barbara handles; and Ian comments on the deadly effects of insecticides, which puts fear into Barbara - they need to get back to the TARDIS and back to normal size fast. While Ian looks for materials to get them out of the lab, Barbara has a close encounter with a fly - the model of the fly looks and acts very realistically.

The Doctor and Susan, meanwhile, are getting into the the lab via a drain pipe from the sink, but as the TARDIS crew is about to reunite, Smithers and Forester enter the lab, and wash their hands, emptying the sink into the pipe where the Doctor and Susan hide... Dangerous Journey adds a time limit element to the story; with the TARDIS crew needing to stop Forester and get back to normal size before Barbara dies from insecticide poisoning.

The Doctor and Susan have survived the Crisis of the emptying of the sink by hiding the overflow pipe, and the TARDIS crew reunite to continue their journey back to the TARDIS. Forester meanwhile has rung up Farrow's boss, pretending to be Farrow, but the local switch operator listens into the call, and suspects that something is going on. At last we get introduced to local busybody Hilda Rowse, and her husband, local Policeman Bert; and at last someone from the world outside the lab is brought into the story.

The TARDIS crew come across the formula for DN6, and the Doctor talks up its dangerous properties (such as not breaking down), upsetting Barbara; with the Doctor coming up with the idea of calling for help using a telephone, they can't be heard by Hilda, but the engaged line raises her suspicisions further. Barbara at last tells the others of her encounter with DN6, with the Doctor concluding that if Barbara was restored to normal size, then the amount of DN6 Barbara absorbed will not be fatal to her. At last the TARDIS crew know of Barbara's predicament, but if they can back to normal size, then Barbara should recover.

Farrow discovers the phone in the lab is off the hook, and Hilda plays a trick, confirming her doubts; Bert agrees, and heads off for the lab. Smithers discovers how harmful DN6 is, and Farrow decides to kill him. The TARDIS crew decide to cause an explosion to attract people's attention to the harmful effects of DN6, causing a canister of DN6 to explode in Forester's face, just as Bert arrives. These scenes of the TARDIS crew working with large items works well, with the props acurrately constructed to represent large versions of everyday objects. The TARDIS crew make it back to the TARDIS, where they return to full size, and Barbara recovers from the DN6 poisoning. Looking at the repaired scanner screen, the Doctor is concerned that only static is showing and not their new location...

As a three part story, the plot of Planet of Giants is fairly thinly stretched, but still works, I suspect that if the scripts for the four part version were published, it would probably show the story to be very padded. I think that the reason why Planet of Giants ended up being produced over the other proposed 'miniscules' stories is that the script provides another threat to deal with, other than the hazards they would face at their reduced sides; with the DN6 plot line also adding another threat to the TARDIS crew with Barbara's poisoning, as well as meaning that the TARDIS crew's actions while at their reduced size have some meaning to the world they are in. As commented previously, the set designs for Planet of Giants are excellent, with the enlarged versions of sets matching up with the normal sized sets. Planet of Giants is a bit of a curiousity piece, showing how well the production team worked with the confines of the budget and studio allocation to produce convincing looking sets and visual effects.

7.8/10

Next time: The TARDIS lands on Earth again, and some old enemies have also dropped in on Earth too...