The word 'alien' has negative connotations, but while it can be prudent to keep in mind Virgil's 'Timeo Danaos et dona ferentes,' it's unwise to judge on appearances, so the idiom 'don't tar all with the same brush,' is an equally relevant one.
Events in season three go back as far as 1665 and forward to 2059, with the immediate present playing a crucial role in one of the more notable two-parters, The Wedding of Sarah Jane Smith, which has a very special guest star.
Her travels with the Doctor(s) and much of her life since has been filled with the unknown, but something she never thought she'd have to deal with is motherhood. It's a challenge at any age, but having a son that's an artificial human created by the Bane makes it a little more difficult still. Luckily, Luke (Tommy Knight) is learning to stand alone against the odds, which he proves more than once.
While all of the stories would classify as 'Adventures', some of them do a much better job with important themes than others do. Some of the better ones include, but are not limited to, the destructive affects of jealousy; being careful what you wish for, especially in anger; the pangs of regret; the desire to feel appreciated and fit in; and the healing power of second chances. Yes, it's still a children's TV show, but that doesn't mean it has to compromise on subtextual depth.
Threats include nanotechnology and a not-too-bright but very determined Judoon police officer, but what I'd run from most are Rani's (Anjli Mohindra) parents, adults who are somewhere between sit-com and soap opera - a useful combination when the script calls for an adult annoyance, but damned aggravating when it doesn't.
6 two-part stories (12 episodes), approx 27 minutes each.
3½ broader horizons out of 5