ACROSS:
1. MISEDUCATE – (caused)* in MITE.
6. DATA – “a tad” reversed.
10. DON JUAN – DON + U in JAN
11. OUT COLD – straightforward charade.
12. SMALL TALK – MALL in STALK
13. METAL – M + ET AL
14. CLOWN – OWN after CL(ass)
15. SET PIECES – which is what bishops are in chess.
17. ENERGISED – E(uropean) + (designer)*
20. GENOA – G + A-ONE reversed.
21. PIPIT – I wasn’t sure of this, but Chambers has it: “to hit with a bullet, etc.; to wound; to kill”.
23. RIVERBANK – 1 VERB inside RANK.
25. TEL AVIV – VALET reversed + IV
26. TOURIST – TO UR IS T(rain)
27. AJAR – A + J + A + R(egina). Dodgy definition perhaps? “Having been opened tentatively” would work but would ruin the surface.
28. ASCENDANCY – (case)* + D in NANCY.
DOWN:
1. MIDAS – M + IDA + S, ref. Princess Ida, G&S opera.
2. SINGAPORE – SING + (opera)*, the surface giving a hint to the clue above!
3. DOUBLE NEGATIVE – nice definition by example here.
4. CANVASS – CANVAS + S.
5. TOOLKIT – L inside TOOK + IT
7. AFOOT – A + FOOT, which had me totally stumped for ages for no reason at all really.
8. ANDALUSIA – (land)* + U (“you”) inside ASIA. Another bad homophone, as it’s pronounced “andal-oo-sia” not “andal-you-sia”.
9. STAMPING GROUND – double def connected by “in”.
14. CLEOPATRA – (pectoral a)*, &lit. if you believe Shakespeare, although most historians say she was bitten on the arm.
16. CONTAGION – (I cannot go)*
18. STRIVES – R in ST. IVES
19. DEVOTEE – hidden in “nationwiDE VOTE Elected”
22. PALMA – L in PA and MA, capital of Majorca.
24. KITTY – double definition.
In 8D I just took “you heard” as signifying the letter “u” for wordplay purposes, even though that is not how it is pronounced in “Andalusia” (which I agree it isn’t).
It was on a bitterly cold night and frosty morning, towards the end of the winter of ’97, that I was awakened by a tugging at my shoulder. It was Holmes. The candle in his hand shone upon his eager, stooping face, and told me at a glance that something was amiss.
“Come, Watson, come!” he cried. “The game is afoot. Not a word! Into your clothes and come!”